CWE-640: Weak Password Recovery Mechanism for Forgotten Password

What is CWE-640?

MITRE CWE

The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.

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Detailed description

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Characteristics

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Common consequences

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Mitigations

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Detection methods

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Representative vulnerabilities

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Official MITRE CWE dataMITRE CWE

Original source fields and evidence from the MITRE CWE record.

Official definition

MITRE CWE

The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.

It is common for an application to have a mechanism that provides a means for a user to gain access to their account in the event they forget their password. Very often the password recovery mechanism is weak, which has the effect of making it more likely that it would be possible for a person other than the legitimate system user to gain access to that user's account. Weak password recovery schemes completely undermine a strong password authentication scheme.

This weakness may be that the security question is too easy to guess or find an answer to (e.g. because the question is too common, or the answers can be found using social media). Or there might be an implementation weakness in the password recovery mechanism code that may for instance trick the system into e-mailing the new password to an e-mail account other than that of the user. There might be no throttling done on the rate of password resets so that a legitimate user can be denied service by an attacker if an attacker tries to recover their password in a rapid succession. The system may send the original password to the user rather than generating a new temporary password. In summary, password recovery functionality, if not carefully designed and implemented can often become the system's weakest link that can be misused in a way that would allow an attacker to gain unauthorized access to the system.

Modes of introduction

  • Architecture and Design: COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.
  • Implementation

Common consequences

  • Access Control

    Gain Privileges or Assume Identity

    An attacker could gain unauthorized access to the system by retrieving legitimate user's authentication credentials.

  • Availability

    DoS: Resource Consumption (Other)

    An attacker could deny service to legitimate system users by launching a brute force attack on the password recovery mechanism using user ids of legitimate users.

  • Integrity, Other

    Other

    The system's security functionality is turned against the system by the attacker.

Mitigations

  • Architecture and DesignMake sure that all input supplied by the user to the password recovery mechanism is thoroughly filtered and validated.
  • Architecture and DesignDo not use standard weak security questions and use several security questions.
  • Architecture and DesignMake sure that there is throttling on the number of incorrect answers to a security question. Disable the password recovery functionality after a certain (small) number of incorrect guesses.
  • Architecture and DesignRequire that the user properly answers the security question prior to resetting their password and sending the new password to the e-mail address of record.
  • Architecture and DesignNever allow the user to control what e-mail address the new password will be sent to in the password recovery mechanism.
  • Architecture and DesignAssign a new temporary password rather than revealing the original password.

Representative vulnerabilities

These examples illustrate this CWE entry and are not an exhaustive list of related vulnerabilities.

  • CVE-2025-1570password reset functionality for a WordPress plugin allows a brute force attack of the one-time password
  • CVE-2024-9302password reset functionality for a WordPress plugin allows a brute force attack of the one-time password
  • CVE-2024-5277password recovery mechanism for AI developer toolkit does not invalidate the reset password token after it is used, allowing attackers to reuse the token to change passwords of victims
  • CVE-2024-38287web conference product resets passwords to random 8-digit values, allowing brute force attacks by retrieving the hash

Sources and references

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