Refactor Login Endpoint to Mitigate Timing Attacks #19
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…sh for non-existent users and ensuring constant timing for password verification
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Pull request overview
This PR refactors the login endpoint to mitigate timing attacks by ensuring password verification takes constant time regardless of whether a user exists. The implementation uses a dummy password hash for non-existent users and checks both user existence and password validity together before returning an error.
Changes:
- Removed early return when user doesn't exist
- Added dummy password hash for non-existent users to maintain constant verification time
- Combined user existence and password validity checks into a single conditional
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This PR refactors the login endpoint to enhance security against timing attacks. When a user does not exist, a dummy password hash is used for verification, ensuring that password checks always take approximately the same time regardless of user existence. Both user existence and password validity are checked together, maintaining constant timing and preventing attackers from inferring valid users based on response time. This change improves authentication security without affecting user experience.