MediaTek Frame Buffer Debugging Interface Memory Overwrite

Product Mediatek 6735
Severity High
CVE Reference N/A
Type Input Validation

Description

MediaTek is a company that provides system-on-chip solutions for wireless communications, HDTV, DVD and Blu-ray. A number of MediaTek clients including Huawei, and Neffos were found to be affected by a vulnerability in the MediaTek Frame Buffer Debugging Interface code.

The '/d/mtkfb' file provides a framebuffer debugging interface which allows the root user to query and configure various frame buffer options. It was found that the 'regw' command can be abused for overwriting arbitrary kernel memory. 

Impact

Local attackers who gain root access can exploit this issue to gain additional capabilities and disable security mechanisms such as SELinux.

Cause

This vulnerability is due to insufficient input validation of user supplied data.

Solution

MediaTek clients can receive the security fix directly from the vendor.

Technical details

Please refer to the attached advisory.

Disclosure Timeline

Date

Summary

2016-10-22

Issue reported to MediaTek.

2016-11-16

MediaTek responded with confirmation of the issue.

2016-11-25

MWR queried MediaTek for the issue status and patch release plan.

2017-03-30

MWR queried MediaTek for the issue status and patch release plan.

2017-03-30

MediaTek confirmed that issue was fixed and a patch was available to its customers.