Catching Cloudflare WARP Leaking Real IPs Through Tor | AI-Native security platform
Cloudflare WARP Gateway leaks real IP addresses through Tor via undocumented HTTP headers.
A security researcher discovered that Cloudflare's managed WARP Gateway service injects HTTP headers (including Cf-Connecting-Ip and the undocumented Cf-Warp-Tag-Id) before traffic enters Tor, exposing users' real IP addresses. The Cf-Warp-Tag-Id header persisted across two sessions linking a Finnish VPS to a French residential connection two hours apart, enabling IP correlation. This is an architectural mismatch where HTTP-layer inspection stamps identifying metadata upstream of TCP-layer anonymization, defeating Tor's anonymity guarantees.
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The lesson from this incident
Full lessonCloudflare's WARP Gateway service was found to inject identifying HTTP headers (Cf-Connecting-Ip and Cf-Warp-Tag-Id) before traffic entered the Tor network, completely defeating Tor's anonymity protections. This represents a fundamental architectural flaw where HTTP-layer inspection occurs upstream of TCP-layer anonymization, creating persistent identifiers that can correlate user sessions across different IP addresses. The issue demonstrates how improper service configuration and inadequate privacy controls can compromise user anonymity even when using privacy-focused tools like Tor.
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Indicators of Compromise
Extracted by AI from the linked source. Not reviewed by an editor. How this works
- ip — 65.109.30.32
- ip — 2a01:e0a:fe2:4de0:fac:5473:377e:1cde