Implementing Runtime Security With Tetragon

Implementing Runtime Security with Tetragon

Overview

Tetragon is a CNCF project under Cilium that provides flexible Kubernetes-aware security observability and runtime enforcement using eBPF. By operating at the Linux kernel level, Tetragon can monitor and enforce policies on process execution, file access, network connections, and system calls with less than 1% performance overhead -- far more efficient than traditional user-space security agents.

When to Use

Trigger phrases:

• "implementing runtime security with tetragon"

• "Implement eBPF-based runtime security observability and enforcement in Kubernete"

• When deploying or configuring implementing runtime security with tetragon capabilities in your environment

• When establishing security controls aligned to compliance requirements

• When building or improving security architecture for this domain

• When conducting security assessments that require this implementation

Prerequisites

• Kubernetes cluster v1.24+ with Helm 3.x installed
• Linux kernel 5.4+ (5.10+ recommended for full eBPF feature support)
• kubectl access with cluster-admin privileges
• Familiarity with eBPF concepts and Kubernetes security primitives

Core Concepts

This section covers core concepts for implementing runtime security with tetragon.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

eBPF-Based Security

Tetragon attaches eBPF programs directly to kernel functions, enabling:

• Process lifecycle tracking: Monitor every process creation, execution, and termination across all pods
• File integrity monitoring: Detect unauthorized reads/writes to sensitive files
• Network observability: Track all TCP/UDP connections with full pod context
• System call filtering: Enforce policies on dangerous syscalls like ptrace, mount, or unshare

TracingPolicy Custom Resources

Tetragon uses TracingPolicy CRDs to define what kernel events to observe and what actions to take:

apiVersion: cilium.io/v1alpha1
kind: TracingPolicy
metadata:
  name: detect-privilege-escalation
spec:
  kprobes:
    - call: "security_bprm_check"
      syscall: false
      args:
        - index: 0
          type: "linux_binprm"
      selectors:
        - matchBinaries:
            - operator: "In"
              values:
                - "/bin/su"
                - "/usr/bin/sudo"
                - "/usr/bin/passwd"
          matchNamespaces:
            - namespace: Pid
              operator: NotIn
              values:
                - "host_ns"
          matchActions:
            - action: Post

Enforcement Actions

Tetragon can take three types of actions directly in the kernel:

1. Sigkill: Immediately terminate the offending process
2. Signal: Send a configurable signal to the process
3. Override: Override the return value of a kernel function to deny an operation

Installation and Configuration

# Install required dependencies
sudo apt-get update && sudo apt-get install -y <tool-name>

Step 1: Install Tetragon with Helm

helm repo add cilium https://helm.cilium.io
helm repo update

helm install tetragon cilium/tetragon \
  --namespace kube-system \
  --set tetragon.enableProcessCred=true \
  --set tetragon.enableProcessNs=true \
  --set tetragon.grpc.address="localhost:54321"

Step 2: Install the Tetragon CLI

GOOS=$(go env GOOS)
GOARCH=$(go env GOARCH)
curl -L --remote-name-all \
  https://github.com/cilium/tetragon/releases/latest/download/tetra-${GOOS}-${GOARCH}.tar.gz
tar -xzvf tetra-${GOOS}-${GOARCH}.tar.gz
sudo install tetra /usr/local/bin/

Step 3: Verify Installation

kubectl get pods -n kube-system -l app.kubernetes.io/name=tetragon
tetra status

Practical Implementation

This section covers practical implementation for implementing runtime security with tetragon.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

Detecting Container Escape Attempts

Create a TracingPolicy to detect processes attempting to escape container namespaces:

apiVersion: cilium.io/v1alpha1
kind: TracingPolicy
metadata:
  name: detect-container-escape
spec:
  kprobes:
    - call: "__x64_sys_setns"
      syscall: true
      args:
        - index: 0
          type: "int"
        - index: 1
          type: "int"
      selectors:
        - matchNamespaces:
            - namespace: Pid
              operator: NotIn
              values:
                - "host_ns"
          matchActions:
            - action: Sigkill

Monitoring Sensitive File Access

Detect reads of sensitive credentials:

apiVersion: cilium.io/v1alpha1
kind: TracingPolicy
metadata:
  name: monitor-sensitive-files
spec:
  kprobes:
    - call: "security_file_open"
      syscall: false
      args:
        - index: 0
          type: "file"
      selectors:
        - matchArgs:
            - index: 0
              operator: "Prefix"
              values:
                - "/etc/shadow"
                - "/etc/kubernetes/pki"
                - "/var/run/secrets/kubernetes.io"
          matchActions:
            - action: Post

Blocking Crypto-Miner Execution

Prevent known crypto-mining binaries from executing:

apiVersion: cilium.io/v1alpha1
kind: TracingPolicy
metadata:
  name: block-cryptominers
spec:
  kprobes:
    - call: "security_bprm_check"
      syscall: false
      args:
        - index: 0
          type: "linux_binprm"
      selectors:
        - matchBinaries:
            - operator: "In"
              values:
                - "/usr/bin/xmrig"
                - "/tmp/xmrig"
                - "/usr/bin/minerd"
          matchActions:
            - action: Sigkill

Observing Events with Tetra CLI

Stream runtime events in real-time:

# Watch all process execution events
kubectl exec -n kube-system ds/tetragon -c tetragon -- \
  tetra getevents -o compact --process-only

# Filter events for a specific namespace
kubectl exec -n kube-system ds/tetragon -c tetragon -- \
  tetra getevents -o compact --namespace production

# Export events in JSON for SIEM integration
kubectl exec -n kube-system ds/tetragon -c tetragon -- \
  tetra getevents -o json | tee /var/log/tetragon-events.json

Integration with SIEM and Alerting

This section covers integration with siem and alerting for implementing runtime security with tetragon.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

Export to Elasticsearch

# tetragon-helm-values.yaml
export:
  stdout:
    enabledCommand: true
    enabledArgs: true
  filenames:
    - /var/log/tetragon/tetragon.log
  elasticsearch:
    enabled: true
    url: "https://elasticsearch.monitoring:9200"
    index: "tetragon-events"

Prometheus Metrics

Tetragon exposes metrics at :2112/metrics:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: tetragon-metrics
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app.kubernetes.io/name: tetragon
  endpoints:
    - port: metrics
      interval: 15s

Key Metrics and Alerts

When NOT to Use

• You need to test the implementation (use performing-* skills)
• Task is about configuring existing tools (use configuring-* skills)
• You need to analyze security events (use analyzing-* skills)
• Task is about building detection rules (use building-* skills)
• You don't have access to the target environment
• Task requires vendor-specific expertise (consult vendor docs)

Red Flags

• Performing actions without explicit written authorization from the asset owner
• Testing against production systems without a defined scope and rules of engagement
• Modifying cloud IAM policies or security groups without approval
• Exposing cloud credentials or secrets in logs or reports
• Running scans that generate excessive API calls and trigger billing alerts

Verification

• All steps executed successfully against a test environment before production use
• Output documented with screenshots or logs demonstrating expected behavior
• Cloud resource changes reverted or documented as intentional
• IAM policies reviewed for least-privilege compliance after testing
• No residual test resources left running (cost and security check)

References

• Tetragon Official Documentation
• Cilium Tetragon GitHub Repository
• CNCF Tetragon Project Page
• eBPF Security Observability with Tetragon - CoreWeave
• Kubernetes Security: eBPF & Tetragon for Runtime Monitoring

Process

1. Analyze the task requirements
2. Apply domain expertise
3. Verify output quality

Anti-Rationalization Table