What is Weak Password Recovery Mechanism (CWE-640)?

TL;DR: Weak Password Recovery Mechanism for Forgotten Password (CWE-640) is a vulnerability that allows attackers to exploit weak mechanisms to recover or change passwords. It can lead to unauthorized access and denial-of-service attacks.

What is Weak Password Recovery Mechanism for Forgotten Password?

Weak Password Recovery Mechanism for Forgotten Password (CWE-640) is a type of vulnerability that occurs when the mechanism to recover or change passwords without knowing the original password is weak. As defined by the MITRE Corporation under CWE-640, and classified by the OWASP Foundation under A07:2025 - Authentication Failures, this weakness allows attackers to gain unauthorized access to user accounts through brute force attacks on security questions or other recovery mechanisms.

Quick Summary

Weak Password Recovery Mechanism for Forgotten Password is a serious vulnerability that can lead to unauthorized access and denial-of-service attacks. It matters because it undermines the integrity of authentication systems and exposes sensitive data. Jump to: What · Why it matters · Where it occurs · Who is affected · Who is NOT affected

Jump to: Quick Summary · Weak Password Recovery Mechanism for Forgotten Password Overview · How Weak Password Recovery Mechanism for Forgotten Password Works · Business Impact of Weak Password Recovery Mechanism for Forgotten Password · Weak Password Recovery Mechanism for Forgotten Password Attack Scenario · How to Detect Weak Password Recovery Mechanism for Forgotten Password · How to Fix Weak Password Recovery Mechanism for Forgotten Password · Framework-Specific Fixes for Weak Password Recovery Mechanism for Forgotten Password · How to Ask AI to Check Your Code for Weak Password Recovery Mechanism for Forgotten Password · Weak Password Recovery Mechanism for Forgotten Password Best Practices Checklist · Weak Password Recovery Mechanism for Forgotten Password FAQ · Vulnerabilities Related to Weak Password Recovery Mechanism for Forgotten Password · References · Scan Your Own Site

Weak Password Recovery Mechanism for Forgotten Password Overview

What

Weak Password Recovery Mechanism for Forgotten Password (CWE-640) is a vulnerability where the mechanism to recover or change passwords without knowing the original password is weak.

Why it matters

This weakness can allow attackers to gain unauthorized access and disrupt system availability through brute force attacks on security questions or other recovery mechanisms.

Where it occurs

It commonly occurs in web applications that implement insecure password recovery processes, such as allowing users to bypass authentication with easily guessable answers.

Who is affected

Web application users who rely on weak password recovery mechanisms are at risk of having their accounts compromised by attackers.

Who is NOT affected

Users and systems that use strong security questions or multi-factor authentication for password recovery are not vulnerable to this weakness.

How Weak Password Recovery Mechanism for Forgotten Password Works

Root Cause

The root cause lies in the implementation of weak mechanisms for recovering forgotten passwords, such as allowing users to bypass security questions with minimal validation.

Attack Flow

1. An attacker identifies a target account.
2. The attacker attempts to reset the password using a weak recovery mechanism.
3. If successful, the attacker gains unauthorized access to the user’s account and can perform malicious actions.

Prerequisites to Exploit

• The system must allow users to bypass authentication with minimal validation.
• Security questions should be easily guessable or not rate-limited.

Vulnerable Code

def reset_password(user_id):
    security_question = input("Enter your security question answer: ")
    if validate_answer(security_question, user_id):
        send_new_password(user_id)

This code allows an attacker to bypass authentication by providing a correct or incorrect answer without proper validation.

Secure Code

def reset_password(user_id):
    security_question = input("Enter your security question answer: ")
    if validate_answer(security_question, user_id) and check_rate_limit(user_id):
        send_new_password(user_id)

The secure code includes rate limiting to prevent brute force attacks and ensures proper validation of the security question.

Business Impact of Weak Password Recovery Mechanism for Forgotten Password

Confidentiality

• Exposed data: Sensitive information such as personal details, financial records, or private communications.
• Example scenario: An attacker gains access to a user’s account and steals confidential documents.

Integrity

• Modified data: Unauthorized changes to user accounts or system configurations.
• Example scenario: An attacker modifies the user’s security questions or resets their password multiple times.

Availability

• Disrupted service: Denial-of-service attacks through repeated attempts to reset passwords.
• Example scenario: The system becomes unavailable due to excessive requests from an attacker trying to bypass authentication.

Weak Password Recovery Mechanism for Forgotten Password Attack Scenario

1. An attacker identifies a user’s account and decides to exploit the weak password recovery mechanism.
2. The attacker sends multiple requests to reset the password using easily guessable answers or common patterns.
3. If successful, the attacker gains unauthorized access to the user’s account and can perform malicious actions such as transferring funds or deleting sensitive data.

How to Detect Weak Password Recovery Mechanism for Forgotten Password

Manual Testing

• Verify that security questions are not easily guessable.
• Check if rate limiting is implemented on password reset attempts.
• Ensure that the recovery process does not allow user-controlled email addresses.

Automated Scanners (SAST / DAST)

Static analysis can identify weak validation logic, while dynamic testing can simulate brute force attacks to detect vulnerabilities.

PenScan Detection

PenScan’s scanner engines such as ZAP and Wapiti can detect weak password recovery mechanisms by simulating attack scenarios.

False Positive Guidance

A finding is a false positive if the system enforces strong security questions or multi-factor authentication, even if it appears vulnerable at first glance.

How to Fix Weak Password Recovery Mechanism for Forgotten Password

• Implement strict validation of security question answers.
• Enforce rate limiting on password reset attempts.
• Use multi-factor authentication to enhance security.
• Ensure that the recovery process does not allow user-controlled email addresses.

Framework-Specific Fixes for Weak Password Recovery Mechanism for Forgotten Password

def validate_answer(answer, user_id):
    if check_rate_limit(user_id) and verify_security_question(answer, user_id):
        return True
    else:
        raise ValueError("Invalid security question answer or rate limit exceeded.")

def send_new_password(user_id):
    # Send new password to the registered email address.

How to Ask AI to Check Your Code for Weak Password Recovery Mechanism for Forgotten Password

Weak Password Recovery Mechanism for Forgotten Password Best Practices Checklist

✅ Implement multi-factor authentication to enhance security. ✅ Enforce rate limiting on password reset attempts. ✅ Use strong, non-easily guessable security questions. ✅ Ensure that the recovery process does not allow user-controlled email addresses. ✅ Regularly audit and update the security of your password recovery mechanisms.

Weak Password Recovery Mechanism for Forgotten Password FAQ

How does a weak password recovery mechanism work?

A weak password recovery mechanism allows attackers to bypass authentication by exploiting vulnerabilities such as easy-to-guess security questions or lack of rate limiting.

What are the consequences of CWE-640 in web applications?

Weak password recovery mechanisms can lead to unauthorized access, data breaches, and service disruptions due to denial-of-service attacks.

How do attackers exploit weak password recovery mechanisms?

Attackers often use brute force techniques or social engineering tactics to bypass security questions and gain access to user accounts.

What are the common signs of a weak password recovery mechanism in code?

Signs include lack of input validation, no rate limiting on failed attempts, and allowing users to control email addresses for password resets.

How can you prevent CWE-640 in web applications?

Implement strong security questions, enforce strict rate limits, and ensure that the recovery process does not allow user-controlled email addresses.

What are some best practices for securing password recovery mechanisms?

Use multi-factor authentication, implement CAPTCHA challenges, and regularly audit the recovery mechanism to identify and fix vulnerabilities.

How can you test your application for weak password recovery mechanisms?

Conduct manual testing by attempting to bypass security questions or reset passwords through various methods, and use automated scanners to detect potential issues.

Vulnerabilities Related to Weak Password Recovery Mechanism for Forgotten Password

References

• MITRE: CWE-640
• OWASP A07:2025 - Authentication Failures
• CAPEC-50
• NVD: National Vulnerability Database

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find Weak Password Recovery Mechanism for Forgotten Password and other risks before an attacker does.