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🔒 fix: Prevent X-Forwarded-For IP spoofing in Rate Limiter - #54

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Sanan507 merged 6 commits into
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jules/fix-rate-limit-ip-spoofing-9241149742628663330
Aug 1, 2026
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🔒 fix: Prevent X-Forwarded-For IP spoofing in Rate Limiter#54
Sanan507 merged 6 commits into
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jules/fix-rate-limit-ip-spoofing-9241149742628663330

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@Sanan507

@Sanan507 Sanan507 commented Aug 1, 2026

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🎯 What: The RateLimitFilter previously trusted the X-Forwarded-For header blindly, allowing clients to spoof their IP address. This PR fixes the vulnerability by validating that the connection comes from an internal network (e.g. proxy) before trusting the header, and correctly parsing proxy chains right-to-left.
⚠️ Risk: An attacker could trivially bypass rate limiting by rotating a spoofed X-Forwarded-For header, allowing a DoS attack against computationally expensive endpoints (like /api/simulations).
🛡️ Solution: The resolveClientIp method now checks if request.getRemoteAddr() is a private/internal IP. If it is, it parses the X-Forwarded-For list from right to left to pick the first non-internal IP, ensuring we grab the real client IP appended by our trusted proxy and ignore any spoofed values. Tests were added to guarantee this behavior.


PR created automatically by Jules for task 9241149742628663330 started by @Sanan507

Update RateLimitFilter to securely parse the proxy chain and ensure
only trusted internal IPs can spoof X-Forwarded-For headers. Added
comprehensive tests to verify fix.

Co-authored-by: Sanan507 <227714367+Sanan507@users.noreply.github.com>
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Project Deployment Actions Updated (UTC)
algorithm-race-visualizer Ready Ready Preview Aug 1, 2026 10:47am

Update RateLimitFilter to securely parse the proxy chain and ensure
only trusted internal IPs can spoof X-Forwarded-For headers. Added
comprehensive tests to verify fix.

Co-authored-by: Sanan507 <227714367+Sanan507@users.noreply.github.com>
Update RateLimitFilter to securely parse the proxy chain and ensure
only trusted internal IPs can spoof X-Forwarded-For headers. Added
comprehensive tests to verify fix.

Co-authored-by: Sanan507 <227714367+Sanan507@users.noreply.github.com>
@Sanan507
Sanan507 merged commit 2310fb7 into master Aug 1, 2026
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@Sanan507
Sanan507 deleted the jules/fix-rate-limit-ip-spoofing-9241149742628663330 branch August 1, 2026 10:51
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2 participants