UNIXY Varnish (cPanel Plugin) – Privilege Escalation (R911-0093)

Type: Privilege Escalation
Location: Local
Impact: Critical
Product: UNIXY cPanel Varnish
Website: http://www.unixy.net
Vulnerable Version: 1.8.4
Fixed Version: 1.8.6
CVE: -
R911: 0093
Date: 2013-11-20
By: Rack911

Product Description:

The UNIXY cPanel plugin comes with a Web interface to manage Varnish via cPanel WHM. The cPanel app takes the complexity out of Varnish in a consolidated one-stop interface. The script allows you to uninstall Varnish, modify Varnish settings, lookup caching stats, refresh the Varnish cache, restart Varnish, and much more!

Vulnerability Description:

A malicious user can escalate their privileges due to a symlink attack when Varnish is disabled by the end user. This flaw is exploitable by both resellers and normal cPanel users. In our testing we were able to obtain an interactive root shell in a matter of seconds.


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

Vulnerable Version:

This vulnerability was tested against UNIXY cPanel Varnish v1.8.4 and is believed to exist in all prior versions.

Fixed Version:

This vulnerability was patched in UNIXY cPanel Varnish v1.8.6.

Vendor Contact Timeline:

2013-10-12: Vendor contacted via email.
2013-10-12: Vendor confirms vulnerability.
2013-11-18: Vendor issues v1.8.6 update.
2013-11-20: Rack911 issues security advisory.