🛡️ Sentinel: [CRITICAL] Fix dummy hash format for timing attacks#54
🛡️ Sentinel: [CRITICAL] Fix dummy hash format for timing attacks#54luisdlopera wants to merge 1 commit into
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When a user is not found, the backend attempted to prevent timing attacks by comparing against a dummy bcrypt hash. However, the dummy hash used was structurally invalid. Because of this, `bcryptjs` would fail-fast instead of performing the CPU-intensive comparison, making the timing mitigation completely ineffective and allowing user enumeration. Replaced the invalid string with a structurally valid pre-computed bcrypt hash.
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🚨 Severity: CRITICAL
💡 Vulnerability: Timing attack leading to user enumeration. The backend attempted to mitigate timing attacks by comparing against a dummy hash when a user is not found. However, the dummy hash was structurally invalid, causing
bcryptjsto fail-fast. This meant that the dummy comparison executed much faster than a real comparison.🎯 Impact: Attackers could enumerate registered emails/users by observing response times.
🔧 Fix: Replaced the invalid dummy string with a valid, pre-computed bcrypt hash.
✅ Verification: Ran backend tests and linters. Checked git status to make sure only the intended files are committed. Included a new Sentinel Journal entry.
PR created automatically by Jules for task 678763443076962770 started by @luisdlopera