google-labs-jules[bot]
8b4280d5dd
Modified `is_private_ip` in `app/utils/network.py` to fail securely by returning True (blocking the request) when a hostname cannot be resolved. The previous implementation failed open, creating a risk for Server-Side Request Forgery (SSRF) and DNS rebinding attacks. Updated corresponding tests to expect the secure behavior. Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
861 B
2025-05-18 - [SSRF Bypass via DNS Resolution Failure]
Vulnerability: The is_private_ip function in app/utils/network.py failed open (returned False) when a hostname could not be resolved (socket.gaierror).
Learning: This fail-open pattern was originally added to allow external domains in tests, but in production, it created a severe SSRF risk. An attacker could bypass SSRF protections by providing a URL that fails to resolve during the security check but resolves later (DNS rebinding), or by exploiting internal routing behaviors via unresolvable addresses.
Prevention: Always fail securely in network authorization functions. If a domain cannot be resolved to verify its safety, the request must be blocked (return True / default-deny). Tests should mock DNS resolution correctly instead of compromising production security logic.