Detect Crawl4AI Docker API Multiple Critical Vulnerabilities (File Write, SSRF, Auth Bypass, XSS, JS Execution) in Elastic Security
Detects exploitation of CVE-2026-56266 affecting Crawl4AI <= 0.8.6 Docker API. The vulnerability bundle includes unauthenticated access (CWE-306), path traversal file write (CWE-22), server-side request forgery (CWE-918), stored/reflected XSS (CWE-79), JavaScript injection/execution (CWE-94), and hardcoded credentials (CWE-798). A public PoC is available. Successful exploitation allows full container compromise, internal network pivoting, and arbitrary file write to the host.
MITRE ATT&CK
Elastic Detection Query
sequence by source.ip with maxspan=5m
[network where event.category == "network" and
destination.port in (11235, 8080, 8000, 8001) and
(
url.path : ("*/crawl*", "*/execute_js*", "*/screenshot*", "*/extract*") or
url.query : ("*127.0.0.1*", "*169.254.169.254*", "*file://*", "*../.*", "*%2e%2e*")
)]
[network where event.category == "network" and
destination.port in (11235, 8080, 8000, 8001) and
http.response.status_code in (200, 201, 500) and
(
url.path : ("*/execute_js*", "*/crawl*") or
url.query : ("*10.*", "*192.168.*", "*172.16.*", "*172.17.*")
)]EQL sequence rule detecting a two-step Crawl4AI exploit pattern: an initial probe to API endpoints followed by successful responses, or SSRF/traversal attempts correlated with HTTP 200/201 responses from the same source IP within 5 minutes.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate sequential API calls from authorized crawl automation pipelines
- Load balancer health checks on Crawl4AI ports generating repeated 200 responses
- CI/CD pipelines running integration tests against Crawl4AI test environments
- Monitoring agents polling Crawl4AI health endpoints on standard ports
Other platforms for CVE-2026-56266
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Crawl4AI Unauthenticated API Access Test
Expected signal: HTTP POST to port 11235 /crawl endpoint with 200 response and no Authorization header in request logs
- Test 2Crawl4AI SSRF via Cloud Metadata Endpoint
Expected signal: Outbound HTTP connection from Crawl4AI container to 169.254.169.254:80; logged in container network flow data and potentially in WAF/proxy logs
- Test 3Crawl4AI Path Traversal File Read via Screenshot Endpoint
Expected signal: HTTP POST to /screenshot or /crawl with file:// URL scheme in request body; response may contain file contents if vulnerable
- Test 4Crawl4AI JavaScript Code Injection via execute_js Endpoint
Expected signal: HTTP POST to /execute_js with js_code parameter containing JavaScript; Crawl4AI process spawning Playwright browser subprocess
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