cPanel – Force Password Change Symlink Privilege Escalation (R911-0183)

Type: Privilege Escalation (Symlink)
Location: Local
Impact: High
Product: cPanel
Website: http://www.cpanel.net
Vulnerable Version: All versions prior to the fixed builds below.
Fixed Version: 11.50.0.27, 11.48.4.6 & 11.46.3.8
CVE: -
R911: 0183
Date: 2015-07-23
By: RACK911 Labs

Product Description:

cPanel is an easy-to-use control panel that gives web hosts and the website owners they serve, the ability to quickly and easily manage their servers and websites. Web Host Manager (WHM) is a part of the cPanel software, often used by resellers and system administrators.

Vulnerability Description:

It is possible for a malicious user to perform a symlink attack against key files on the server to escalate their privileges to root access. This is allowed to happen during the Force Password Change function that performs various root file operations within the user home directory.

Note:

The cPanel advisory (intentionally) understates the severity of this vulnerability! Interactive root access can be obtained in a matter of seconds.

Impact:

We have deemed this vulnerability to be rated as HIGH due to the fact that root access can be obtained.

Vulnerable Version:

This vulnerability is believed to exist in all versions prior to the fixed versions below.

Fixed Version:

This vulnerability was patched in cPanel versions 11.50.0.27, 11.48.4.6 & 11.46.3.8.

Vendor Contact Timeline:

2015-05-14: Vendor contacted via email.
2015-05-15: Vendor confirms vulnerability.
2015-07-20: Vendor issues updates to all builds.
2015-07-23: RACK911 Labs issues security advisory.