PasswordResetRequest - Improvements

[dpfaffenbauer]

Problem Statement
The password reset flow contains multiple security-critical weaknesses.

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Problem 1 – User Enumeration

Description & Impact
Different responses are returned depending on whether a user exists or not.
This makes account enumeration trivial.

Impact

• Enables preparation for targeted attacks (credential stuffing, phishing).

CWE

• CWE-204 – Observable Response Discrepancy

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Problem 2 – Weak Reset Token Generation

Description

• Use of MD5 for token generation.
• Use of mt_rand() (not a cryptographically secure random number generator).
• Token is based on predictable components:
  • User ID
  • Login identifier
  • Timestamp

Reference
https://www.php.net/manual/en/function.mt-rand.php

Impact

• Reset tokens are potentially guessable.
• Account takeover is possible.

CWE

• CWE-640 – Weak Password Recovery Mechanism
• CWE-330 / CWE-338 – Insufficiently Random / Weak PRNG

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Problem 3 – No Rate Limiting

Description

• Password reset can be triggered an unlimited number of times.
• No limitation per IP, account, or identifier.

Impact

• User enumeration at scale.
• Mail bombing / denial of service.
• Increased likelihood of successful token attacks.

CWE

• CWE-307 – Improper Restriction of Excessive Authentication Attempts

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Problem 4 – Missing Expiration (TTL)

Description

• Reset token remains valid until it is overwritten or used.
• No time-based validity window is enforced.

Impact

• Long-lived reset links.
• Increased risk in case of token leakage.

CWE

• CWE-613 – Insufficient Session Expiration

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Problem 5 – Reset Token Stored in Plaintext

Description

• passwordResetHash contains the usable reset token in clear text.
• In case of SQL injection or database leakage, account takeover is trivial
  (especially when combined with missing TTL and cleanup).

Impact

• Direct password reset possible via database read access.

CWE

• CWE-640 – Weak Password Recovery Mechanism

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Mitigation (Overall)

• Always return a uniform response, regardless of user existence.
• Generate reset tokens using random_bytes().
• Store only hashed tokens, never raw values.
• Enforce:
  • Token expiration (TTL)
  • Single-use tokens
  • Rate limiting

@raphael-kat @papillo-solutions