SRC-2018-0031 : Vanilla Forums ImportController index file_exists Unserialize Remote Code Execution Vulnerability

CVE ID:

CVE-2018-19501

CVSS Score:

6.6, (AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H)

Affected Vendors:

Vanilla

Affected Products:

Vanilla Forums

Vulnerability Details:

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Vanilla Forums. Authentication is required to exploit this vulnerability, however the authentication can be bypassed.

The specific flaw exists within the index function of the ImportController class. The issue results in an unserialize via a crafted phar archive. An attacker can leverage this vulnerability to execute code under the context of the web server.

Vendor Response:

Vanilla has issued an update to correct these vulnerabilities. More details can be found at:
https://github.com/vanilla/vanilla/commit/7a26ccf15fd6be4cdf2d0f6ec8aad1c4b6f1d694

Disclosure Timeline:

• 2018-08-16 - Vulnerability reported to Vanilla
• 2018-08-17 - Vulnerability patched
• 2018-11-23 - Coordinated public release of advisory

Proof of Concept:

https://hackerone.com/reports/410237

Credit:

This vulnerability was discovered by Steven Seeley (mr_me) of Source Incite