Detect GitLab SSRF Exploitation (CVE-2021-22175) in Elastic Security
Detects exploitation of CVE-2021-22175, a Server-Side Request Forgery (SSRF) vulnerability in GitLab. An attacker can craft requests that cause the GitLab server to make HTTP requests to internal or external resources, potentially exposing cloud metadata endpoints, internal services, or facilitating lateral movement. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
MITRE ATT&CK
Elastic Detection Query
sequence by source.ip with maxspan=5m
[network where event.category == "network" and event.type == "connection"
and (
url.path : ("*/import*", "*/hook*", "*/webhook*", "*/integrations*")
or url.query : ("*url=http*", "*import_url=*", "*remote=http*")
)
and http.response.status_code in (200, 302, 400, 403, 500)
]
[network where event.category == "network"
and (
destination.ip : ("169.254.169.254", "127.0.0.1", "10.0.0.0/8", "192.168.0.0/16", "172.16.0.0/12")
or dns.question.name : ("metadata.google.internal", "169.254.169.254")
)
and source.ip : ("*gitlab*")
]EQL sequence detection correlating inbound SSRF-targeted requests to GitLab with subsequent outbound connections from the GitLab server to internal or cloud metadata IP ranges, confirming successful SSRF exploitation.
Data Sources
Required Tables
False Positives & Tuning
- GitLab's own internal health checks to loopback addresses
- Legitimate webhook deliveries where the receiving server is on a private network
- Authorized cloud metadata access by GitLab for cloud-native deployments
- Security monitoring agents that probe internal endpoints from the GitLab host
Other platforms for CVE-2021-22175
Testing Methodology
Validate this detection against 3 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 1GitLab SSRF via Project Import URL - AWS Metadata
Expected signal: Outbound HTTP GET to 169.254.169.254 from GitLab server process; network flow record showing connection to 169.254.0.0/16 from GitLab host; GitLab production.log entry with import_url containing metadata endpoint
- Test 2GitLab SSRF via Webhook Creation - Internal Service Probe
Expected signal: Network connection from GitLab server to 192.168.1.1:8500 visible in network flow data; GitLab web_hooks table entry with internal IP URL; web server access log showing webhook API POST with internal URL in body
- Test 3GitLab SSRF via Remote Mirror - Loopback File Access
Expected signal: GitLab application log entries showing file:// or gopher:// scheme in remote mirror URL; database record in remote_mirrors table with dangerous URL scheme; error log entries from GitLab attempting to process the invalid/dangerous URL
Unlock Pro Content
Get the full detection package for CVE-2021-22175 including response playbook, investigation guide, and atomic red team tests.