Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in Revive Adserver

Published: 2019-05-28 | Updated: 2020-07-17
Risk High
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2019-5440
Exploitation vector Network
Public exploit N/A
Vulnerable software
Revive Adserver
Web applications / Other software

Vendor OpenX Source

Security Advisory

This security advisory describes one high risk vulnerability.

1) Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2019-5440

CWE-ID: CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Exploit availability: No


The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

Use of cryptographically weak PRNG in the password recovery token generation of Revive Adserver < v4.2.1 causes a potential authentication bypass attack if an attacker exploits the password recovery functionality. In lib/OA/Dal/PasswordRecovery.php, the function generateRecoveryId() generates a password reset token that relies on the PHP uniqid function and consequently depends only on the current server time, which is often visible in an HTTP Date header.


Install update from vendor's website.

Vulnerable software versions

Revive Adserver: 4.2.0

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.