CVE-2025-6216: Alltena Allegra Auth Bypass Vulnerability

CVE-2025-6216 Overview

CVE-2025-6216 is a critical authentication bypass vulnerability affecting Alltena Allegra project management software. The vulnerability exists within the calculateTokenExpDate function used in the password recovery mechanism, allowing remote attackers to bypass authentication without any credentials.

The flaw stems from the application's reliance on predictable values when generating password reset tokens. By exploiting this weakness, an unauthenticated attacker can craft valid password reset tokens to gain unauthorized access to user accounts, potentially compromising the entire application and its data.

Critical Impact

Remote attackers can bypass authentication entirely by predicting password reset tokens, gaining unauthorized access to any user account including administrative accounts.

Affected Products

• Alltena Allegra (versions prior to 8.1.4)
• Alltena Allegra (versions prior to 7.5.2)

Discovery Timeline

• 2025-06-21 - CVE-2025-6216 published to NVD
• 2025-08-18 - Last updated in NVD database

Technical Details for CVE-2025-6216

Vulnerability Analysis

This authentication bypass vulnerability (CWE-640: Weak Password Recovery Mechanism for Forgotten Password) allows unauthenticated remote attackers to compromise user accounts through the password recovery feature. The vulnerability requires no user interaction and can be exploited directly over the network.

The calculateTokenExpDate function generates password reset tokens using predictable values, which fundamentally undermines the security of the password recovery mechanism. When a password reset is requested, the application creates a token that should be cryptographically random and unpredictable. However, due to this flaw, attackers can predict or enumerate these tokens.

Successful exploitation allows attackers to reset passwords for arbitrary user accounts, including administrator accounts, resulting in complete authentication bypass and potential full system compromise.

Root Cause

The root cause is CWE-640: Weak Password Recovery Mechanism for Forgotten Password. The calculateTokenExpDate function relies on predictable values—such as timestamps, sequential identifiers, or insufficiently random seeds—when generating password reset tokens. This design flaw means that an attacker who understands the token generation algorithm can calculate valid tokens without having access to the user's email or other verification methods.

Attack Vector

The attack is network-based and can be executed remotely without authentication. An attacker targets the password recovery endpoint and exploits the predictable token generation by:

1. Initiating a password reset request for a known username or email address
2. Predicting or calculating the password reset token based on the weak generation algorithm
3. Submitting the predicted token to the password reset confirmation endpoint
4. Successfully resetting the victim's password without access to their email

The vulnerability was reported through the Zero Day Initiative program as ZDI-CAN-27104 and published as ZDI-25-410.

Detection Methods for CVE-2025-6216

Indicators of Compromise

• Multiple password reset requests targeting different user accounts from the same IP address
• Successful password reset completions without corresponding email link clicks in mail server logs
• Anomalous authentication patterns following password reset requests
• Sequential or rapid-fire requests to the password recovery endpoint

Detection Strategies

• Monitor web application logs for unusual patterns in password reset request frequency
• Implement rate limiting alerts on the password recovery endpoint
• Correlate password reset token submissions with email delivery confirmations
• Alert on password resets for privileged accounts from unexpected sources

Monitoring Recommendations

• Enable detailed logging for all authentication and password recovery events
• Deploy web application firewall (WAF) rules to detect password reset enumeration attempts
• Monitor for brute-force patterns against the token validation endpoint
• Implement anomaly detection for user account modifications following password resets

How to Mitigate CVE-2025-6216

Immediate Actions Required

• Upgrade Alltena Allegra to version 8.1.4 or 7.5.2 (for the respective release branches)
• Review recent password reset activity for signs of exploitation
• Force password resets for privileged and administrative accounts
• Consider temporarily disabling the password recovery feature until patches are applied

Patch Information

Alltena has released security patches addressing this vulnerability. Users should upgrade to Allegra version 8.1.4 or 7.5.2 depending on their current release branch. Detailed patch information is available in the Alltena Release Notes.

Workarounds

• Disable the self-service password recovery feature and require administrative password resets
• Implement additional authentication factors for password reset confirmation
• Restrict access to the password recovery endpoint via network controls
• Deploy a web application firewall with rules to detect and block suspicious password reset patterns

# Example: Restrict password recovery endpoint access via web server
# Apache configuration to limit access to password reset functionality
<Location "/allegra/passwordRecovery">
    # Limit to internal networks only until patch is applied
    Require ip 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
    # Or disable entirely
    # Require all denied
</Location>