Advisory ID: 
BACKDROP-SA-CORE-2019-002
Date: 
Wednesday, Jan 16th, 2019
Vulnerability: 
Arbitrary PHP code execution
Versions affected: 
  • Backdrop core versions prior to 1.12.1 and 1.11.5

A remote code execution vulnerability exists in PHP's built-in phar stream wrapper when performing file operations on an untrusted phar:// URI.

Some Backdrop code (core, contrib, and custom) may be performing file operations on insufficiently validated user input, thereby being exposed to this vulnerability.

This vulnerability is mitigated by the fact that such code paths typically require access to an administrative permission or an atypical configuration.

.phar added to dangerous extensions list

The .phar file extension has been added to Backdrop's dangerous extensions list, which means that any such file uploaded to a Backdrop file field will automatically be converted to a text file (with the .txt extension) to prevent it from being executed. This is similar to how Backdrop handles file uploads with a .php extension.

Another SA was released today, see also:

Solution: 

Upgrade your site to the most recent version of Backdrop core.  Download available on the Backdrop CMS 1.12.1 release page.  See the update instructions, if needed.

Reported By: 
Fixed By: 
Coordinated By: