Type: Authentication Bypass
Vulnerable Version: 18.104.22.168 and earlier.
Fixed Version: 22.214.171.124
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.
WHM fails to restrict access to the Root SSH Key manager and allows a malicious user to generate a new key under /root/.ssh/ and overwrite an existing key if the file name is known or if .id_dsa is used by default.
Proof of Concept:
1. Log into WHM using a reseller account.
2. Open the following URL after the WHM session:
We have deemed this vulnerability to be rated as MEDIUM due to the fact that private keys under /root/.ssh/ can be overwritten. Right now it is not possible to use a private key generated by this exploit to gain access.
This vulnerability was tested against cPanel (WHM) v126.96.36.199.
This vulnerability was patched in version 188.8.131.52 or possibly a few builds earlier, we’re not sure since cPanel stopped communicating with us regarding the matter and decided to silently fix. All users are urged to upgrade as soon as possible.
Vendor Contact Timeline:
2013-05-04: Vendor contacted via email.
2013-05-06: Vendor confirms vulnerability.
2013-05-10: Vendor issues v184.108.40.206 update.
2013-05-13: Rack911 issues security advisory.