Zero-day vulnerability in vBulletin

Security bypass
CVE-2013-6129

Known malware:

PHP/Exploit.CVE-2013-6129.A virus.

Vulnerability details

Advisory: SB2013082701 - Security bypass in vBulletin

Vulnerable component: vBulletin

CVE-ID: CVE-2013-6129

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Description:

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The weakness exists due to an error in the upgrade.php script. By using the customerid, htmldata[password], htmldata[confirmpassword], and htmldata[email] parameters, a remote attacker can create administrative accounts.

Successful exploitation of the vulnerability results in security bypass on the vulnerable system.

Note: the vulnerability was being actively exploited.

Public Exploits:

- vBulletin 4.1.x - '/install/upgrade.php' Security Bypass [Exploit-DB]

External links:

http://www.vbulletin.com/forum/forum/vbulletin-announcements/vbulletin-announcements_aa/3991423-vbul...
https://www.helpnetsecurity.com/2013/10/09/dangerous-vbulletin-exploit-in-the-wild/

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.