A vulnerability in Parallels Plesk could allow an unauthenticated, remote attacker to execute arbitrary PHP script on a targeted system with the privileges of the web service.
The vulnerability is due to an unsafe configuration of PHP in the affected application. An unauthenticated, remote attacker could exploit the vulnerability by sending malicious HTTP responses to the targeted system containing malicious Content-Length fields. The processing of the Content-Length fields by the application could trigger the execution of supplied PHP code within the security context of the web service.
Proof-of-concept code is publicly available.
Parallels has confirmed the vulnerability is a variation of the CVE-2012-1823 vulnerability which is documented in Alert 25816 at the following link: Response from Parallels #43928803
Parallels has also confirmed that all current supported versions of Parallels Plesk Panel 9.5 or later are not vulnerable from this variation.
Customers are advised to upgrade to the latest version of Parallels Plesk Panel.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.