<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Runtime-Security on lo0 — Tech Blog</title><link>https://blog.lo0.es/en/tags/runtime-security/</link><description>Recent content in Runtime-Security on lo0 — Tech Blog</description><generator>Hugo -- gohugo.io</generator><language>en</language><lastBuildDate>Tue, 19 May 2026 05:00:00 +0200</lastBuildDate><atom:link href="https://blog.lo0.es/en/tags/runtime-security/index.xml" rel="self" type="application/rss+xml"/><item><title>Tetragon: Cilium's security cousin that sees every syscall in the kernel</title><link>https://blog.lo0.es/en/posts/tetragon-cilium-security-syscalls-kernel/</link><pubDate>Tue, 19 May 2026 05:00:00 +0200</pubDate><guid>https://blog.lo0.es/en/posts/tetragon-cilium-security-syscalls-kernel/</guid><description>&lt;h2 id="tldr">TL;DR&lt;/h2>
&lt;p>&lt;a href="https://tetragon.io/">Tetragon&lt;/a> is the runtime security and observability engine that the Cilium project published as a companion to the CNI. Its job is not to route packets, Cilium is already there for that, but to &lt;strong>observe what happens inside the node&amp;rsquo;s processes in real time&lt;/strong>: which binary runs in each pod, which files it opens, which syscalls it invokes, which capabilities it asks for, which network connections it establishes, which kernel modules get loaded. It does this by loading eBPF programs into the kernel&amp;rsquo;s hook points (kprobes, tracepoints, uprobes, LSM hooks) and filtering the relevant events &lt;strong>inside the kernel itself&lt;/strong> with a declarative language expressed as a CRD (&lt;code>TracingPolicy&lt;/code> and &lt;code>TracingPolicyNamespaced&lt;/code>). The result is a stream of events enriched with Kubernetes metadata (pod, namespace, labels) that costs less than 1% of CPU and, the thing that sets Tetragon apart from the competition, can &lt;strong>block actions inside the kernel&lt;/strong>, killing the process with &lt;code>SIGKILL&lt;/code> or overwriting a syscall&amp;rsquo;s return value, &lt;strong>before they finish executing&lt;/strong>, with no race conditions. Against Falco (which parses syscalls in userspace, 5-10% overhead, detection-only), Tetragon is &amp;ldquo;cheaper and with enforcement&amp;rdquo;; against the bare kernel, it is &amp;ldquo;a declarative layer your operations colleague can read&amp;rdquo;. This article is the extensive introduction you need to take it on seriously: architecture, all the hooks and selectors, the operating modes, a guide to use cases (exec auditing, sensitive file access, container escape, cryptomining, rootkit detection, network observability) and the traps you see in production.&lt;/p>
&lt;blockquote>
&lt;p>This article is part 2 of the eBPF series. Part 1, &lt;a href="https://blog.lo0.es/en/posts/ebpf-zero-to-cilium-kernel-tcp-ip-bypass/">eBPF from zero to Cilium: how the kernel learned to skip its own TCP/IP stack&lt;/a>, covered basic eBPF, the networking hooks (XDP, TC, sock_ops), how Cilium implements the datapath and the BGP Control Plane v2 CRDs. Here we take those same eBPF hooks and use them for something different: &lt;strong>observing and, if needed, stopping&lt;/strong> what the cluster&amp;rsquo;s processes do.&lt;/p>
&lt;/blockquote>
&lt;h2 id="the-analogy-auditd-on-steroids-in-ebpf">The analogy: auditd on steroids in eBPF&lt;/h2>
&lt;p>Anyone who has spent a few years administering Linux has used &lt;code>auditd&lt;/code>. It is the classic kernel subsystem for auditing syscalls: you configure a rule with &lt;code>auditctl&lt;/code> (for instance, &amp;ldquo;monitor any &lt;code>open&lt;/code> on &lt;code>/etc/shadow&lt;/code>&amp;rdquo;) and the kernel sends events to a userspace daemon that persists them. It works, but it has two limitations that weigh heavily on modern Kubernetes clusters:&lt;/p>
&lt;ol>
&lt;li>&lt;strong>No Kubernetes context.&lt;/strong> auditd reports processes by PID and UID. Knowing which pod, which namespace, which image, which labels, the information that actually matters when responding to an incident, requires correlating afterwards with data from cri-o or containerd. It is operationally miserable.&lt;/li>
&lt;li>&lt;strong>No granular enforcement.&lt;/strong> auditd can generate events, but it cannot take the decision to kill the offending process before the syscall finishes. You leave that to a higher layer that reads the events, processes them and kills the process… if it gets there in time. A race by design.&lt;/li>
&lt;/ol>
&lt;p>Tetragon is &lt;strong>auditd on steroids&lt;/strong>: the same conceptual ideas, hooks on syscalls and events to userspace, but implemented with modern eBPF, with filtering inside the kernel so you do not pay the cost of waking the daemon for every irrelevant syscall, with Kubernetes metadata injected by an agent that knows the cluster, and with actions executed inside the kernel itself without waiting for userspace to decide. If the rule says &amp;ldquo;kill any process that opens &lt;code>/etc/shadow&lt;/code> from the &lt;code>prod&lt;/code> namespace&amp;rdquo;, the decision is taken in the kernel kprobe and &lt;code>SIGKILL&lt;/code> is delivered before the &lt;code>open&lt;/code> completes. There is no race; there is no window between detection and action.&lt;/p>
&lt;h2 id="what-tetragon-is-architecturally">What Tetragon is, architecturally&lt;/h2>
&lt;p>Tetragon is an agent deployed as a &lt;code>DaemonSet&lt;/code> (one pod per node) and a set of CRDs that define the policies to apply. The agent has four responsibilities:&lt;/p>
&lt;ol>
&lt;li>&lt;strong>Load eBPF programs&lt;/strong> into the hook points the active TracingPolicies demand.&lt;/li>
&lt;li>&lt;strong>Maintain a cache of Kubernetes metadata&lt;/strong> (pods, namespaces, labels) by reading the API server, so it can enrich every event with the right context.&lt;/li>
&lt;li>&lt;strong>Collect the events&lt;/strong> the eBPF programs emit (via ring buffers) and serialise them.&lt;/li>
&lt;li>&lt;strong>Export the events&lt;/strong> to configurable destinations: &lt;code>stdout&lt;/code> JSON (typical in sidecars or log-collection agents), gRPC streaming (to consume them from Hubble or another consumer), a file, or Fluentd/Loki/SIEM.&lt;/li>
&lt;/ol>
&lt;p>The eBPF programs are not written by the user. Tetragon generates the bytecode from the TracingPolicies: it reads the declarative policy, decides which hooks to attack, which arguments to read from the kernel, which filters to apply inline and which actions to execute. The user only writes &lt;strong>YAML&lt;/strong>.&lt;/p>
&lt;div class="diagram" style="max-width:720px;margin:1.5rem auto;">
&lt;svg viewBox="0 0 720 280" xmlns="http://www.w3.org/2000/svg" role="img" aria-label="Tetragon architecture">
&lt;style>.title{font:600 13px sans-serif;fill:#222}.lbl{font:600 12px sans-serif;fill:#222}.sm{font:11px sans-serif;fill:#555}.box{stroke:#444;stroke-width:1.4}.k{fill:#ffe9d6}.u{fill:#d6eaff}.p{fill:#d9f5d6}.api{fill:#e9d6f5}.arr{stroke:#666;stroke-width:1.4;fill:none;marker-end:url(#h)}&lt;/style>
&lt;defs>&lt;marker id="h" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="6" markerHeight="6" orient="auto">&lt;path d="M0,0 L10,5 L0,10 z" fill="#666"/>&lt;/marker>&lt;/defs>
&lt;text x="360" y="20" text-anchor="middle" class="title">Tetragon: control and data planes on a node&lt;/text>
&lt;rect x="40" y="50" width="200" height="70" rx="6" class="box k"/>
&lt;text x="140" y="70" text-anchor="middle" class="lbl">eBPF programs&lt;/text>
&lt;text x="140" y="90" text-anchor="middle" class="sm">kprobes, tracepoints,&lt;/text>
&lt;text x="140" y="105" text-anchor="middle" class="sm">uprobes, LSM&lt;/text>
&lt;rect x="40" y="160" width="200" height="60" rx="6" class="box u"/>
&lt;text x="140" y="183" text-anchor="middle" class="lbl">Tetragon agent&lt;/text>
&lt;text x="140" y="203" text-anchor="middle" class="sm">reads events from the ring buffer&lt;/text>
&lt;rect x="290" y="160" width="180" height="60" rx="6" class="box api"/>
&lt;text x="380" y="183" text-anchor="middle" class="lbl">Kubernetes API&lt;/text>
&lt;text x="380" y="203" text-anchor="middle" class="sm">pods, namespaces, labels&lt;/text>
&lt;rect x="510" y="50" width="180" height="70" rx="6" class="box p"/>
&lt;text x="600" y="70" text-anchor="middle" class="lbl">TracingPolicy CRDs&lt;/text>
&lt;text x="600" y="90" text-anchor="middle" class="sm">declarative YAML&lt;/text>
&lt;text x="600" y="105" text-anchor="middle" class="sm">cluster or namespaced&lt;/text>
&lt;rect x="510" y="160" width="180" height="60" rx="6" class="box u"/>
&lt;text x="600" y="183" text-anchor="middle" class="lbl">Exporters&lt;/text>
&lt;text x="600" y="203" text-anchor="middle" class="sm">stdout, gRPC, file, SIEM&lt;/text>
&lt;path class="arr" d="M510,80 L240,80"/>
&lt;text x="375" y="74" text-anchor="middle" class="sm">policies → bytecode&lt;/text>
&lt;path class="arr" d="M140,120 L140,160"/>
&lt;text x="160" y="143" text-anchor="middle" class="sm">events&lt;/text>
&lt;path class="arr" d="M290,190 L240,190"/>
&lt;text x="265" y="184" text-anchor="middle" class="sm">enrich&lt;/text>
&lt;path class="arr" d="M240,180 L510,180"/>
&lt;text x="375" y="174" text-anchor="middle" class="sm">enriched events&lt;/text>
&lt;text x="360" y="255" text-anchor="middle" class="sm">The arrows show data flow. TracingPolicies are compiled into eBPF programs;&lt;/text>
&lt;text x="360" y="270" text-anchor="middle" class="sm">events travel kernel → agent → exporter, decorated with K8s metadata along the way.&lt;/text>
&lt;/svg>
&lt;/div>
&lt;p>This separation of declarative policy → generated eBPF bytecode is what makes Tetragon usable. Writing eBPF programs by hand is a specialist&amp;rsquo;s job; writing a &lt;code>TracingPolicy&lt;/code> is the job of an SRE with a good example in front of them.&lt;/p>
&lt;h2 id="the-two-crds-tracingpolicy-and-tracingpolicynamespaced">The two CRDs: TracingPolicy and TracingPolicyNamespaced&lt;/h2>
&lt;p>Tetragon exposes exactly two main CRDs:&lt;/p>
&lt;ul>
&lt;li>&lt;code>TracingPolicy&lt;/code> (cluster-scoped, &lt;code>cilium.io/v1alpha1&lt;/code>): applies to the whole cluster, every node, every pod. Suitable for platform policies (the whole cluster must be audited the same way): for example, &amp;ldquo;log every &lt;code>execve&lt;/code> in every pod&amp;rdquo; or &amp;ldquo;kill any process that tries to load a kernel module&amp;rdquo;.&lt;/li>
&lt;li>&lt;code>TracingPolicyNamespaced&lt;/code> (namespaced, same group and version): defined inside a namespace and applied only to the pods of that namespace. Suitable for policies with per-tenant autonomy: for example, &amp;ldquo;in the &lt;code>prod-payments&lt;/code> namespace, kill any outbound &lt;code>connect&lt;/code> to an IP outside the corporate range&amp;rdquo;.&lt;/li>
&lt;/ul>
&lt;p>Both CRDs have exactly the same internal structure. The difference is one of scope. The distinction was introduced precisely to allow multi-tenancy: the central security team defines cluster-wide &lt;code>TracingPolicy&lt;/code> objects and each tenant can add its own with &lt;code>TracingPolicyNamespaced&lt;/code> without needing cluster-admin permissions.&lt;/p>
&lt;h2 id="anatomy-of-a-tracingpolicy">Anatomy of a TracingPolicy&lt;/h2>
&lt;p>A policy is made up of:&lt;/p>
&lt;ol>
&lt;li>&lt;strong>Hook points&lt;/strong>: which kernel events to observe.&lt;/li>
&lt;li>&lt;strong>Arguments&lt;/strong>: which data to read when the hook fires.&lt;/li>
&lt;li>&lt;strong>Selectors&lt;/strong>: filters evaluated inside the kernel to discard irrelevant events and, optionally, execute actions when they match.&lt;/li>
&lt;/ol>
&lt;h3 id="supported-hook-points">Supported hook points&lt;/h3>
&lt;p>The official documentation lists five families of hook points:&lt;/p>
&lt;ul>
&lt;li>&lt;code>kprobes&lt;/code>: hook a kernel function. Syscalls are a particular case (when &lt;code>syscall: true&lt;/code>) because their ABI differs from that of internal functions. Typical examples: &lt;code>sys_open&lt;/code>, &lt;code>sys_openat&lt;/code>, &lt;code>sys_connect&lt;/code>, &lt;code>tcp_connect&lt;/code>, &lt;code>do_mount&lt;/code>, &lt;code>commit_creds&lt;/code>. It is the most versatile hook and the one used 80% of the time.&lt;/li>
&lt;li>&lt;code>tracepoints&lt;/code>: hook static tracepoints compiled into the kernel. More stable across kernel versions than kprobes (they do not depend on function names that can change). Examples: &lt;code>syscalls/sys_enter_openat&lt;/code>, &lt;code>sched/sched_process_exec&lt;/code>.&lt;/li>
&lt;li>&lt;code>uprobes&lt;/code>: hook functions in userspace libraries or binaries. They serve to observe runtime primitives such as libssl functions, libc, the Go runtime, the JVM.&lt;/li>
&lt;li>&lt;strong>USDT &lt;code>tracepoints&lt;/code>&lt;/strong> (User Statically Defined Tracepoints): static tracepoints defined in userspace binaries (like those MySQL, PostgreSQL and OpenJDK expose). Useful for application observability.&lt;/li>
&lt;li>&lt;code>lsmHooks&lt;/code> (LSM, Linux Security Module): hooks of the LSM subsystem, where SELinux/AppArmor plug in. They allow security policies very similar to traditional MAC but programmable with eBPF. Example: &lt;code>file_open&lt;/code>, &lt;code>inode_unlink&lt;/code>, &lt;code>socket_bind&lt;/code>.&lt;/li>
&lt;/ul>
&lt;h3 id="arguments">Arguments&lt;/h3>
&lt;p>Every hook can read the arguments of the function it is attached to. The supported types cover the primitives (&lt;code>int&lt;/code>, &lt;code>uint64&lt;/code>, &lt;code>bool&lt;/code>, &lt;code>string&lt;/code>, &lt;code>char_buf&lt;/code>) and higher abstractions (&lt;code>file&lt;/code>, &lt;code>path&lt;/code>, &lt;code>sock&lt;/code>, &lt;code>linux_binprm&lt;/code>, &lt;code>capability&lt;/code>, &lt;code>bpf_attr&lt;/code>, &lt;code>cred&lt;/code>). The high-level types are pointers to kernel structures that Tetragon knows how to parse; instead of having to read an offset, you write &lt;code>type: file&lt;/code> and Tetragon gives you the full path of the descriptor&amp;rsquo;s file.&lt;/p>
&lt;p>There is an important capability detail: on kernels ≥ 5.4, Tetragon can read &lt;strong>up to 327,360 bytes&lt;/strong> of an argument if the large buffers flag is enabled. That is the difference between being able to audit &lt;code>execve&lt;/code> with all of its long argv complete versus truncating them at 256 bytes and losing context.&lt;/p>
&lt;h3 id="selectors-filtering-in-the-kernel">Selectors: filtering in the kernel&lt;/h3>
&lt;p>Selectors are what make Tetragon cheap. Without them, every syscall on the node would fire an event that would travel kernel → ring buffer → agent → processed → filtered → discarded. With selectors, the filtering happens &lt;strong>inside the eBPF program itself, in the kernel&lt;/strong>, and only the events that matter reach userspace.&lt;/p>
&lt;p>The available selectors include:&lt;/p>
&lt;ul>
&lt;li>&lt;code>matchArgs&lt;/code>: filters by an argument&amp;rsquo;s value. Operators: &lt;code>Equal&lt;/code>, &lt;code>NotEqual&lt;/code>, &lt;code>Prefix&lt;/code>, &lt;code>Postfix&lt;/code>, &lt;code>GreaterThan&lt;/code>, &lt;code>LessThan&lt;/code>, &lt;code>Mask&lt;/code>, &lt;code>SPort&lt;/code> (source port), &lt;code>DPort&lt;/code> (dest port), &lt;code>Family&lt;/code> (AF_INET vs AF_INET6), &lt;code>State&lt;/code> (socket state).&lt;/li>
&lt;li>&lt;code>matchPIDs&lt;/code>: filters by PID; useful for targeted observation.&lt;/li>
&lt;li>&lt;code>matchBinaries&lt;/code>: filters by the binary executing the syscall (absolute path), with &lt;code>Operator: In&lt;/code>, &lt;code>NotIn&lt;/code>, &lt;code>Prefix&lt;/code>. Essential for avoiding noise from legitimate system processes.&lt;/li>
&lt;li>&lt;code>matchNamespaces&lt;/code>: filters by Linux namespace (Pid, Mnt, Net, Ipc, Cgroup, User). It allows policies specific to processes in containers versus the host.&lt;/li>
&lt;li>&lt;code>matchCapabilities&lt;/code>: filters by the process&amp;rsquo;s effective capabilities. Block actions requiring &lt;code>CAP_SYS_ADMIN&lt;/code> that run in pods that should not have them.&lt;/li>
&lt;li>&lt;code>matchNamespaceChanges&lt;/code>: detects namespace changes (typical of container escape).&lt;/li>
&lt;li>&lt;code>matchCapabilityChanges&lt;/code>: detects capability changes (privilege escalation).&lt;/li>
&lt;li>&lt;code>matchActions&lt;/code>: the actions executed when all the preceding matchers hit.&lt;/li>
&lt;/ul>
&lt;h3 id="actions-from-a-simple-post-to-sigkill">Actions: from a simple Post to Sigkill&lt;/h3>
&lt;p>When a selector matches, an &lt;code>action&lt;/code> is executed. Tetragon defines several:&lt;/p>
&lt;ul>
&lt;li>&lt;code>Post&lt;/code>: emits an event to userspace (the observability case). It supports &lt;code>rateLimit&lt;/code> to avoid flooding the agent if the condition fires a thousand times per second. The syntax accepts &lt;code>5&lt;/code> for 5 seconds, &lt;code>5m&lt;/code> for 5 minutes, &lt;code>1h&lt;/code> for 1 hour.&lt;/li>
&lt;li>&lt;code>Sigkill&lt;/code>: sends &lt;code>SIGKILL&lt;/code> to the offending process from inside the kernel, &lt;strong>before the syscall completes&lt;/strong>. This is the only thing that guarantees enforcement without a race.&lt;/li>
&lt;li>&lt;code>Override&lt;/code>: overwrites the syscall&amp;rsquo;s return value. Useful for making the process believe the syscall failed (&lt;code>Override -EPERM&lt;/code>) without killing it. A better experience for apps that can handle errors; worse for apps that assume success.&lt;/li>
&lt;li>&lt;code>Signal&lt;/code>: sends any arbitrary signal (not just &lt;code>SIGKILL&lt;/code>).&lt;/li>
&lt;li>&lt;code>NoPost&lt;/code>: does not emit an event, useful when combined with another selector that does emit and you only want the action without duplicated telemetry.&lt;/li>
&lt;li>&lt;strong>&lt;code>FollowFD&lt;/code> and &lt;code>UnfollowFD&lt;/code>&lt;/strong>: mark a file descriptor to follow its lifecycle and enrich subsequent events with the original path. Useful for auditing &amp;ldquo;which process read this file after opening it&amp;rdquo;.&lt;/li>
&lt;li>&lt;code>TrackSock&lt;/code> and &lt;code>UntrackSock&lt;/code>: the same for sockets.&lt;/li>
&lt;li>&lt;strong>&lt;code>GetUrl&lt;/code> and &lt;code>DnsLookup&lt;/code>&lt;/strong>: make HTTP requests or DNS resolutions from the kernel. Designed for integrations with external systems (security webhooks, IP reputation lookups).&lt;/li>
&lt;li>&lt;code>NotifyEnforcer&lt;/code> and &lt;code>CleanupEnforcerNotification&lt;/code>: communication with Tetragon&amp;rsquo;s enforcement subsystem for complex actions.&lt;/li>
&lt;/ul>
&lt;h2 id="modes-detection-vs-enforcement">Modes: detection vs enforcement&lt;/h2>
&lt;p>A policy can be declared in one of two explicit modes:&lt;/p>
&lt;ul>
&lt;li>&lt;code>enforce&lt;/code>: enforcement actions (&lt;code>Sigkill&lt;/code>, &lt;code>Override&lt;/code>, &lt;code>Signal&lt;/code>) are active. This is production.&lt;/li>
&lt;li>&lt;code>monitoring&lt;/code>: enforcement actions are ignored; only &lt;code>Post&lt;/code> events are emitted. This is the &amp;ldquo;let us see what would happen if this were switched on&amp;rdquo; mode, critical for testing policies without breaking applications.&lt;/li>
&lt;/ul>
&lt;p>Control is done with the &lt;code>spec.options[].name: policy-mode&lt;/code> field and &lt;code>value: monitoring&lt;/code> or &lt;code>enforce&lt;/code>. It is the best practice: start in &lt;code>monitoring&lt;/code>, collect events for days, tune the selectors until no false positives come out, and only then switch to &lt;code>enforce&lt;/code>.&lt;/p>
&lt;h2 id="full-example-blocking-writes-to-etcpasswd-in-the-prod-namespace">Full example: blocking writes to &lt;code>/etc/passwd&lt;/code> in the prod namespace&lt;/h2>
&lt;p>A realistic policy, commented line by line:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicyNamespaced&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">block-passwd-write&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">namespace&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">prod&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;fd_install&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># kernel function, not a syscall&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># file descriptor&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;file&amp;#34;&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># struct file*&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;Equal&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/etc/passwd&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Sigkill &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># kills the process&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">rateLimit&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;1m&amp;#34;&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># max once per minute&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">options&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">policy-mode&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">value&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">enforce &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># enforcement mode active&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;code>fd_install&lt;/code> runs every time a process obtains a new file descriptor; the second argument is the file&amp;rsquo;s &lt;code>file&lt;/code> struct. Tetragon knows how to resolve it to its absolute path. The &lt;code>matchArgs&lt;/code> compares that path with &lt;code>/etc/passwd&lt;/code>. If it matches, &lt;code>Sigkill&lt;/code> kills the process before the descriptor even becomes usable. &lt;code>rateLimit: 1m&lt;/code> stops the agent from saturating if a malicious application tries it in a loop.&lt;/p>
&lt;h2 id="common-use-cases">Common use cases&lt;/h2>
&lt;p>Now to real use. These are the six cases that show up in any serious Tetragon deployment in 2026.&lt;/p>
&lt;h3 id="1-execution-auditing-execve">1. Execution auditing (&lt;code>execve&lt;/code>)&lt;/h3>
&lt;p>The most basic use case and, even so, the most valuable. Which binaries are running in each pod? In a container that is supposed to run only &lt;code>nginx&lt;/code>, suddenly seeing an &lt;code>sh&lt;/code> or a &lt;code>wget&lt;/code> is almost always a red flag.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">audit-execve&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">tracepoints&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">subsystem&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sched&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">event&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sched_process_exec&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">4&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">linux_binprm &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># struct linux_binprm*&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># events only, no enforcement&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>With no filters: every &lt;code>execve&lt;/code> in the cluster generates an event. With K8s metadata, the event includes pod, namespace, container, image, labels. You turn it into a stream of events towards your SIEM and set up rules: &amp;ldquo;alert if I see &lt;code>sh&lt;/code>, &lt;code>bash&lt;/code>, &lt;code>nc&lt;/code>, &lt;code>curl&lt;/code>, &lt;code>wget&lt;/code> or &lt;code>python&lt;/code> running in any pod of the &lt;code>prod-api&lt;/code> namespace&amp;rdquo;.&lt;/p>
&lt;p>An enforcement variant: instead of &lt;code>Post&lt;/code>, use &lt;code>matchBinaries&lt;/code> with &lt;code>Operator: NotIn&lt;/code> and a whitelist, plus &lt;code>Sigkill&lt;/code> if the binary is not on the list. A very rigid box, but effective in pods that are &amp;ldquo;single-binary&amp;rdquo; (like a Go microservice).&lt;/p>
&lt;h3 id="2-sensitive-file-access">2. Sensitive file access&lt;/h3>
&lt;p>Detecting (or blocking) reads and writes on critical files: &lt;code>/etc/shadow&lt;/code>, &lt;code>/etc/kubernetes/&lt;/code>, Secret mounts, &lt;code>/var/run/docker.sock&lt;/code>, &lt;code>/proc/*/cmdline&lt;/code>.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">sensitive-file-access&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;security_file_open&amp;#34;&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># LSM-ish via kprobe&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;file&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;Prefix&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/etc/shadow&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/var/run/secrets/&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/var/run/docker.sock&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchBinaries&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;NotIn&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/usr/bin/kubelet&amp;#34;&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># legitimate kubelet access&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>The &lt;code>matchBinaries: NotIn&lt;/code> is important: kubelet and other legitimate node agents access these paths constantly and would generate noise. We filter those out in the kernel.&lt;/p>
&lt;p>In enforcement: swap &lt;code>Post&lt;/code> for &lt;code>Override&lt;/code> with &lt;code>argError: -1&lt;/code> (&lt;code>EPERM&lt;/code>), so that the open fails but the offending process stays alive and produces the error so that tracing tools pick it up.&lt;/p>
&lt;h3 id="3-unauthorised-outbound-network-connections">3. Unauthorised outbound network connections&lt;/h3>
&lt;p>Detecting outbound connections to destinations outside the corporate range. Useful for spotting data exfiltration or malware command-and-control.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicyNamespaced&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">block-external-egress&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">namespace&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">prod&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;tcp_connect&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sock&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;NotDAddr&amp;#34;&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># destination NOT in these CIDRs&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;10.0.0.0/8&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;192.168.0.0/16&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;172.16.0.0/12&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Sigkill&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">options&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">policy-mode&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">value&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">enforce&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>This kills any attempt at a TCP connection to an IP that is not in the corporate CIDRs, in the &lt;code>prod&lt;/code> namespace. Cilium already does this with NetworkPolicy, but Tetragon has two complementary advantages:&lt;/p>
&lt;ul>
&lt;li>It gives you the process that attempted the connection, not just &amp;ldquo;pod X tried to connect to Y&amp;rdquo;.&lt;/li>
&lt;li>It also works for exotic protocols where NetworkPolicy is less expressive.&lt;/li>
&lt;/ul>
&lt;h3 id="4-container-escape-detection">4. Container escape detection&lt;/h3>
&lt;p>Container escape is the operational nightmare: a process inside a container manages to break the isolation (via a kernel exploit, a badly set capability, a misconfigured &lt;code>hostPath&lt;/code> mount) and gain access to the host. Three typical signals:&lt;/p>
&lt;ul>
&lt;li>A namespace change on the process (it leaves the container&amp;rsquo;s &lt;code>pid&lt;/code> namespace).&lt;/li>
&lt;li>&lt;strong>&lt;code>setns&lt;/code> or &lt;code>unshare&lt;/code>&lt;/strong> in non-init processes.&lt;/li>
&lt;li>&lt;strong>Access to &lt;code>/proc/1/root&lt;/code> or &lt;code>/dev/&lt;/code>&lt;/strong> from a container.&lt;/li>
&lt;/ul>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">detect-container-escape&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;__x64_sys_setns&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">true&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchNamespaces&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">namespace&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Pid&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">NotIn&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="p">[&lt;/span>&lt;span class="s2">&amp;#34;host_ns&amp;#34;&lt;/span>&lt;span class="p">]&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># only processes NOT in the host pid namespace&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Sigkill&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;__x64_sys_unshare&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">true&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchNamespaceChanges&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">unshare&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">true&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;code>__x64_sys_setns&lt;/code> targeting the host namespace from a process in a container is practically always malicious (legitimate containers do not need this at runtime).&lt;/p>
&lt;h3 id="5-cryptomining">5. Cryptomining&lt;/h3>
&lt;p>Mining processes have fairly recognisable profiles:&lt;/p>
&lt;ul>
&lt;li>Processes with names like &lt;code>xmrig&lt;/code>, &lt;code>minerd&lt;/code>, &lt;code>cgminer&lt;/code>, or legitimate processes such as &lt;code>python&lt;/code> running CPU-intensive scripts.&lt;/li>
&lt;li>Outbound connections to known mining pools (a public list of IPs and domains).&lt;/li>
&lt;li>Anomalous use of &lt;code>/dev/cpu_dma_latency&lt;/code> to avoid throttling.&lt;/li>
&lt;/ul>
&lt;p>A combined policy:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">detect-cryptomining&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">tracepoints&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">subsystem&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sched&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">event&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sched_process_exec&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">4&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">linux_binprm&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">4&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;Postfix&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/xmrig&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/minerd&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/cgminer&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Sigkill&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;tcp_connect&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;sock&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;DPort&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="p">[&lt;/span>&lt;span class="s2">&amp;#34;3333&amp;#34;&lt;/span>&lt;span class="p">,&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;5555&amp;#34;&lt;/span>&lt;span class="p">,&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;7777&amp;#34;&lt;/span>&lt;span class="p">,&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;14444&amp;#34;&lt;/span>&lt;span class="p">]&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># common pool ports&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># log only&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>The double policy: kill binaries with the classic names (belt) and log connections to pool ports (braces), so you also get an alert when someone renames &lt;code>xmrig&lt;/code> to &lt;code>nginx-helper&lt;/code> or uses exotic ports.&lt;/p>
&lt;h3 id="6-detecting-rootkits-and-suspicious-kernel-modules">6. Detecting rootkits and suspicious kernel modules&lt;/h3>
&lt;p>Modern rootkits load kernel modules to patch functions (hide processes, hide network connections, hide files). Detecting them:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">kernel-module-load&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;do_init_module&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;string&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;security_kernel_read_file&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">false&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;file&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchArgs&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;Equal&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="p">[&lt;/span>&lt;span class="s2">&amp;#34;READING_MODULE&amp;#34;&lt;/span>&lt;span class="p">]&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>In a &amp;ldquo;well configured&amp;rdquo; Kubernetes cluster no new kernel modules get loaded at runtime; any event here is highly suspicious. Combine with enforcement on machines where modules should be fixed: &lt;code>Sigkill&lt;/code> for whoever tries to load one.&lt;/p>
&lt;h3 id="bonus-detecting-third-party-modification-of-ebpf-maps">Bonus: detecting third-party modification of eBPF maps&lt;/h3>
&lt;p>As a 2025-2026 trend: loading malicious eBPF programs to hide presence. Tetragon can observe the bpf syscall:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-yaml" data-lang="yaml">&lt;span class="line">&lt;span class="cl">&lt;span class="nt">apiVersion&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">cilium.io/v1alpha1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">kind&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">TracingPolicy&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">metadata&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">name&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">audit-bpf-syscalls&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w">&lt;/span>&lt;span class="nt">spec&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">kprobes&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">call&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;__x64_sys_bpf&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">syscall&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="kc">true&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">args&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">0&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">int &lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="c"># bpf cmd&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">index&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="m">1&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">type&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">bpf_attr&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">selectors&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">matchBinaries&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">operator&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="s2">&amp;#34;NotIn&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">values&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/usr/bin/cilium-agent&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/usr/bin/tetragon&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="s2">&amp;#34;/usr/bin/bpftool&amp;#34;&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>&lt;span class="nt">matchActions&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="w"> &lt;/span>- &lt;span class="nt">action&lt;/span>&lt;span class="p">:&lt;/span>&lt;span class="w"> &lt;/span>&lt;span class="l">Post&lt;/span>&lt;span class="w">
&lt;/span>&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Any process that is &lt;strong>not&lt;/strong> one of the legitimate agents loading eBPF programs: you want to know about it.&lt;/p>
&lt;h2 id="comparison-with-falco">Comparison with Falco&lt;/h2>
&lt;p>&lt;a href="https://falco.org/">Falco&lt;/a> is the closest competitor: it is also runtime security for Kubernetes, also originally based on eBPF (and before that on kernel modules), also with declarative policies. Three years ago they were functionally similar. In 2026 the divergence is clear:&lt;/p>
&lt;table>
&lt;thead>
&lt;tr>
&lt;th>Dimension&lt;/th>
&lt;th>Tetragon&lt;/th>
&lt;th>Falco&lt;/th>
&lt;/tr>
&lt;/thead>
&lt;tbody>
&lt;tr>
&lt;td>Philosophy&lt;/td>
&lt;td>Cilium-native, integrated&lt;/td>
&lt;td>Standalone, generic&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Filtering&lt;/td>
&lt;td>In the kernel (eBPF)&lt;/td>
&lt;td>Parsing in userspace&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Typical overhead&lt;/td>
&lt;td>&lt;strong>&amp;lt;1% CPU&lt;/strong>&lt;/td>
&lt;td>5-10% CPU&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Enforcement&lt;/td>
&lt;td>&lt;strong>Yes, in-kernel (Sigkill, Override)&lt;/strong>&lt;/td>
&lt;td>Not native (depends on plugins)&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Race conditions&lt;/td>
&lt;td>No (action atomic with the syscall)&lt;/td>
&lt;td>Yes, in enforcement via plugins&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>False positive rate&lt;/td>
&lt;td>Low (K8s context in the kernel)&lt;/td>
&lt;td>Higher (parsing afterwards)&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Detection latency&lt;/td>
&lt;td>5-26 ms&lt;/td>
&lt;td>~10 ms (more constant)&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Ecosystem maturity&lt;/td>
&lt;td>Young, growing&lt;/td>
&lt;td>Mature, plenty of material&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Community&lt;/td>
&lt;td>Cilium / CNCF Incubating&lt;/td>
&lt;td>CNCF Graduated&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>Integrations&lt;/td>
&lt;td>Hubble native&lt;/td>
&lt;td>Falcosidekick, many&lt;/td>
&lt;/tr>
&lt;tr>
&lt;td>CRDs per policy&lt;/td>
&lt;td>TracingPolicy / Namespaced&lt;/td>
&lt;td>No CRDs; rules in YAML&lt;/td>
&lt;/tr>
&lt;/tbody>
&lt;/table>
&lt;p>&lt;strong>When to choose each one&lt;/strong>:&lt;/p>
&lt;ul>
&lt;li>&lt;strong>Tetragon&lt;/strong> if you already use Cilium, if you need enforcement in the kernel (not detection-only), if overhead matters to you (workloads with many syscalls), and if you value the Hubble integration. Container escape and cryptomining detection is where its advantage over Falco shows up most.&lt;/li>
&lt;li>&lt;strong>Falco&lt;/strong> if you want a tool independent of the CNI, if you need the catalogue of ready-made rules and the wide community, if your cluster is not Cilium, or if the integration with SIEMs and ready-made notifiers (Falcosidekick) saves you work.&lt;/li>
&lt;li>&lt;strong>Both&lt;/strong> if the organisation is large: Falco for breadth of detection, Tetragon for surgical enforcement on critical workloads. That is what you see most in companies that have spent years with Falco and add Tetragon for specific cases.&lt;/li>
&lt;/ul>
&lt;h2 id="hubble--tetragon-unified-observability">Hubble + Tetragon: unified observability&lt;/h2>
&lt;p>&lt;a href="https://docs.cilium.io/en/stable/observability/hubble/">Hubble&lt;/a> is Cilium&amp;rsquo;s traffic observability component: it shows L3-L7 flow logs with zero impact on latency. Tetragon exposes its events over gRPC with the same format and vocabulary as Hubble, which allows you to:&lt;/p>
&lt;ul>
&lt;li>See them in the same UI (Hubble UI shows Tetragon events as one more &amp;ldquo;layer&amp;rdquo;).&lt;/li>
&lt;li>Correlate network events (Hubble) with process events (Tetragon) on the same timeline.&lt;/li>
&lt;li>Export them together to Loki/Tempo/SIEM as a single stream.&lt;/li>
&lt;/ul>
&lt;p>The key synergy: Hubble tells you &amp;ldquo;this pod made a TCP connection to 1.2.3.4:80&amp;rdquo;. Tetragon tells you &amp;ldquo;this pod ran &lt;code>curl 1.2.3.4&lt;/code> from a &lt;code>bash&lt;/code> binary launched by &lt;code>pid 1234&lt;/code>&amp;rdquo;. Together they give you the full story.&lt;/p>
&lt;h2 id="deployment-and-operation">Deployment and operation&lt;/h2>
&lt;h3 id="helm">Helm&lt;/h3>
&lt;p>The canonical install with Helm:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-bash" data-lang="bash">&lt;span class="line">&lt;span class="cl">helm repo add cilium https://helm.cilium.io
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">helm install tetragon cilium/tetragon &lt;span class="se">\
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="se">&lt;/span> --namespace kube-system &lt;span class="se">\
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="se">&lt;/span> --set tetragon.exportFilename&lt;span class="o">=&lt;/span>/var/log/tetragon/tetragon.log &lt;span class="se">\
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="se">&lt;/span> --set tetragon.exportFileMaxSizeMB&lt;span class="o">=&lt;/span>&lt;span class="m">50&lt;/span> &lt;span class="se">\
&lt;/span>&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="se">&lt;/span> --set tetragon.exportFileRotationInterval&lt;span class="o">=&lt;/span>24h
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Tetragon deploys its &lt;code>DaemonSet&lt;/code>, its CRDs and a service for Hubble. By default, it exposes the events on the agent pod&amp;rsquo;s &lt;code>stdout&lt;/code> (any cluster log aggregator picks them up).&lt;/p>
&lt;h3 id="the-tetra-cli">The &lt;code>tetra&lt;/code> CLI&lt;/h3>
&lt;p>Tetragon ships a CLI called &lt;code>tetra&lt;/code> for interactive investigation:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-bash" data-lang="bash">&lt;span class="line">&lt;span class="cl">&lt;span class="c1"># real-time stream of the node&amp;#39;s events&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">tetra getevents -o compact --pods &amp;lt;pod-name&amp;gt;
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="c1"># structured JSON events to process with jq&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">tetra getevents -o json --since 5m --namespace prod
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="c1"># view loaded policies&lt;/span>
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">tetra tracingpolicy list
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>It is the best tool for debugging policies in &lt;code>monitoring&lt;/code> before moving them to &lt;code>enforce&lt;/code>.&lt;/p>
&lt;h3 id="exporting-to-a-siem">Exporting to a SIEM&lt;/h3>
&lt;p>Three usual routes:&lt;/p>
&lt;ul>
&lt;li>&lt;strong>stdout + log aggregator&lt;/strong>: the agent writes JSON to stdout, Fluent Bit/Vector picks it up and sends it to Splunk/Datadog/Elastic. Simple, works with any logging infrastructure.&lt;/li>
&lt;li>&lt;strong>gRPC streaming&lt;/strong>: for low-latency integrations. A gRPC consumer of your own or Hubble Relay.&lt;/li>
&lt;li>&lt;strong>File + rotation&lt;/strong>: for air-gapped environments or regulatory audits that require persistent logs with controlled rotation.&lt;/li>
&lt;/ul>
&lt;h3 id="performance">Performance&lt;/h3>
&lt;p>Published benchmarks consistently place Tetragon at &lt;strong>&amp;lt;1% of the node&amp;rsquo;s CPU&lt;/strong> under real workloads, compared with &lt;strong>5-10% for Falco&lt;/strong> under the same workloads. The reason is the architectural separation: Tetragon filters in the kernel and only carries the events that actually matter to userspace; Falco carries every syscall to userspace and filters there. On clusters with thousands of pods making hundreds of thousands of syscalls per second, the difference shows up on the bill.&lt;/p>
&lt;h2 id="common-operational-traps">Common operational traps&lt;/h2>
&lt;h3 id="permanent-monitoring">Permanent &lt;code>monitoring&lt;/code>&lt;/h3>
&lt;p>The biggest trap is &lt;strong>never reaching &lt;code>enforce&lt;/code>&lt;/strong>: starting well with policies in monitoring, collecting events, tuning selectors, and then never switching. The result: you have detection without prevention, exactly what Falco gave you without paying Tetragon&amp;rsquo;s complexity. If you are going to use Tetragon, plan the road to enforce for the critical policies.&lt;/p>
&lt;h3 id="selectors-that-are-too-lax">Selectors that are too lax&lt;/h3>
&lt;p>A policy with a single &lt;code>matchActions: Post&lt;/code> and no specific selectors generates events for &lt;strong>every&lt;/strong> syscall of the chosen hook. On a serious node that means &lt;strong>tens of thousands per second&lt;/strong>, which fill logs, saturate exporters and hide the signal in the noise. Always start with strict filters (&lt;code>matchBinaries&lt;/code>, &lt;code>matchNamespaces&lt;/code>, &lt;code>matchPIDs&lt;/code>) and open up once you know what you are looking for.&lt;/p>
&lt;h3 id="a-kernel-that-is-too-old">A kernel that is too old&lt;/h3>
&lt;p>Tetragon needs modern eBPF features. Kernels &amp;lt; 5.4 do not have the large buffer support (needed for &lt;code>execve&lt;/code> with complete argv). Kernels &amp;lt; 5.10 do not have many of the LSM hooks. &lt;strong>Kernel 5.15+ is the recommended minimum for production&lt;/strong> and 6.1+ to have every feature.&lt;/p>
&lt;h3 id="hooks-on-renamed-kernel-functions">Hooks on renamed kernel functions&lt;/h3>
&lt;p>kprobes are tied to kernel function names that &lt;strong>can change between versions&lt;/strong>. A policy that uses &lt;code>__x64_sys_setns&lt;/code> can fail silently on a kernel where the function is called &lt;code>__do_sys_setns&lt;/code>. Solutions: use static tracepoints where they are available (more stable), or keep alternative policies with several &lt;code>call&lt;/code> entries for compatibility.&lt;/p>
&lt;h3 id="sigkill-in-critical-namespaces">&lt;code>Sigkill&lt;/code> in critical namespaces&lt;/h3>
&lt;p>Applying &lt;code>Sigkill&lt;/code> to processes in &lt;code>kube-system&lt;/code> or &lt;code>cilium-system&lt;/code> can break the cluster. Enforcement policies must &lt;strong>explicitly exclude&lt;/strong> the platform namespaces with &lt;code>matchNamespaces&lt;/code> Operator: &lt;code>NotIn&lt;/code>, or limit the scope with &lt;code>TracingPolicyNamespaced&lt;/code> to make sure they do not act on systems they should not.&lt;/p>
&lt;h3 id="missing-ratelimit">Missing &lt;code>rateLimit&lt;/code>&lt;/h3>
&lt;p>A policy without a rateLimit on &lt;code>Post&lt;/code> can suffer a catastrophic fan-out if the condition is met millions of times in an instant (typical in attack loops or application bugs). The agent saturates, events are lost, logs overflow. &lt;strong>Always put a sensible &lt;code>rateLimit&lt;/code> on detection policies&lt;/strong>, especially on high-frequency hooks such as &lt;code>tcp_connect&lt;/code> or &lt;code>execve&lt;/code>.&lt;/p>
&lt;h2 id="what-we-have-not-covered-upcoming-articles">What we have not covered (upcoming articles)&lt;/h2>
&lt;ul>
&lt;li>&lt;strong>eBPF LSM hooks&lt;/strong> in depth: how they relate to SELinux/AppArmor and when Tetragon is the right tool versus classic MAC.&lt;/li>
&lt;li>&lt;strong>Hubble UI with a Tetragon overlay&lt;/strong>: configuring the UI to show process observability and network observability on the same timeline.&lt;/li>
&lt;li>&lt;strong>Integration with OPA/Kyverno&lt;/strong>: how Tetragon complements admission policy engines (Kyverno validates at admission; Tetragon validates at runtime).&lt;/li>
&lt;li>&lt;strong>Forensics with eBPF&lt;/strong>: combining Tetragon with tools such as Beyla or OpenTelemetry to trace the full chain of an incident from the initial connection to the final syscall.&lt;/li>
&lt;/ul>
&lt;h2 id="references">References&lt;/h2>
&lt;p>Official documentation (May 2026):&lt;/p>
&lt;ul>
&lt;li>&lt;a href="https://tetragon.io/">Tetragon — official site&lt;/a> — entry point.&lt;/li>
&lt;li>&lt;a href="https://tetragon.io/docs/concepts/tracing-policy/">Tetragon docs — Tracing Policy&lt;/a> — conceptual reference.&lt;/li>
&lt;li>&lt;a href="https://tetragon.io/docs/concepts/tracing-policy/hooks/">Tetragon docs — Hook points&lt;/a> — kprobes, tracepoints, uprobes, LSM, USDT.&lt;/li>
&lt;li>&lt;a href="https://tetragon.io/docs/concepts/tracing-policy/selectors/">Tetragon docs — Selectors&lt;/a> — full filter reference.&lt;/li>
&lt;li>&lt;a href="https://tetragon.io/docs/concepts/tracing-policy/mode/">Tetragon docs — Enforcement Mode&lt;/a>.&lt;/li>
&lt;li>&lt;a href="https://tetragon.io/docs/concepts/tracing-policy/k8s-filtering/">Tetragon docs — Kubernetes Identity Aware Policies&lt;/a> — &lt;code>TracingPolicyNamespaced&lt;/code>.&lt;/li>
&lt;li>&lt;a href="https://github.com/cilium/tetragon">Tetragon GitHub&lt;/a>.&lt;/li>
&lt;/ul>
&lt;p>Comparisons and analysis:&lt;/p>
&lt;ul>
&lt;li>&lt;a href="https://www.scitepress.org/Papers/2025/142727/142727.pdf">Comparative Analysis of eBPF-Based Runtime Security Monitoring (SciTePress paper 2025)&lt;/a> — a benchmark with independent numbers.&lt;/li>
&lt;li>&lt;a href="https://www.armosec.io/blog/best-ebpf-security-solutions-runtime-protection/">Best eBPF Security Solutions for Kubernetes (ARMO, 2026)&lt;/a> — Falco vs Tetragon vs KubeArmor comparison.&lt;/li>
&lt;li>&lt;a href="https://medium.com/@mughal.asim/falco-vs-tetragon-a-runtime-security-showdown-for-kubernetes-a0e9fb9f30a0">Falco vs. Tetragon (Asim Mirza, Medium)&lt;/a> — analysis with use cases.&lt;/li>
&lt;li>&lt;a href="https://asecurityengineer.com/posts/deep-dive-into-tetragon/">Deep Dive into Tetragon (A Security Engineer)&lt;/a> — a walk through the inside of the agent.&lt;/li>
&lt;li>&lt;a href="https://medium.com/@mughal.asim/tetragon-series-part-2-enforcing-sensitive-file-access-with-a-namespaced-tracingpolicy-3c2f617ec912">Tetragon Series, Part 2: Enforcing Sensitive File Access (Medium)&lt;/a>.&lt;/li>
&lt;/ul>
&lt;p>Ecosystem:&lt;/p>
&lt;ul>
&lt;li>&lt;a href="https://docs.cilium.io/en/stable/observability/hubble/">Cilium Hubble — network observability&lt;/a>.&lt;/li>
&lt;li>&lt;a href="https://falco.org/">Falco — official site&lt;/a> — the other big name in the field.&lt;/li>
&lt;li>&lt;a href="https://kubearmor.io/">KubeArmor&lt;/a> — the third option, with AppArmor + eBPF.&lt;/li>
&lt;/ul>
&lt;p>Cross-references:&lt;/p>
&lt;ul>
&lt;li>Part 1 of the series: &lt;a href="https://blog.lo0.es/en/posts/ebpf-zero-to-cilium-kernel-tcp-ip-bypass/">eBPF from zero to Cilium: how the kernel learned to skip its own TCP/IP stack&lt;/a> — the eBPF fundamentals we take as read here.&lt;/li>
&lt;li>&lt;a href="https://blog.lo0.es/en/posts/kubernetes-cilium-bgp-services-without-ingress/">Kubernetes with Cilium BGP: services reachable without Ingress&lt;/a> — the starting point of the Cilium ecosystem on this blog.&lt;/li>
&lt;/ul></description></item></channel></rss>