CVE-2019-5440 : What You Need to Know

Revive Adserver < 4.2.1 uses a cryptographically weak PRNG in generating password recovery tokens, potentially leading to an authentication bypass attack.

Understanding CVE-2019-5440

Revive Adserver's vulnerability lies in the insecure PRNG used for password recovery token generation.

What is CVE-2019-5440?

The vulnerability in Revive Adserver < 4.2.1 allows attackers to bypass authentication by exploiting the password recovery feature due to the insecure PRNG used in token generation.

The Impact of CVE-2019-5440

Malicious actors can potentially bypass authentication by manipulating password recovery tokens.
The vulnerability exposes sensitive user accounts to unauthorized access.

Technical Details of CVE-2019-5440

Revive Adserver's vulnerability in password recovery token generation.

Vulnerability Description

Revive Adserver < 4.2.1 uses a cryptographically insecure PRNG for generating password recovery tokens.
The generateRecoveryId() function in lib/OA/Dal/PasswordRecovery.php relies on PHP uniqid function, which solely depends on the server time.

Affected Systems and Versions

Product: Revive Adserver
Vendor: Revive
Versions Affected: < 4.2.1

Exploitation Mechanism

Attackers exploit the password recovery feature to manipulate the insecurely generated tokens.

Mitigation and Prevention

Steps to address and prevent the CVE-2019-5440 vulnerability.

Immediate Steps to Take

Upgrade Revive Adserver to version 4.2.1 or higher to mitigate the vulnerability.
Monitor and restrict access to the password recovery feature.

Long-Term Security Practices

Implement strong password policies and encourage regular password updates.
Conduct security audits to identify and address potential vulnerabilities.

Patching and Updates

Regularly update and patch Revive Adserver to ensure the latest security fixes are in place.