bastille-42.remote-OTA.txt

Bastille Tracking Number 42
CVE-2017-9498

Overview

With root access on a Motorola MX011ANM set-top box, an attacker can push arbitrary firmware updates to XR11 remotes.



Affected Platforms:

- Motorola MX011ANM, firmware version MX011AN_2.9p6s1_PROD_sey
- Xfinity XR11-20 Voice Remote



Proof-of-Concept

An attacker can modify known files to upload an arbitrary firmware image to a target XR11 remote.



Test Environment:

- Motorola MX011ANM, firmware version MX011AN_2.9p6s1_PROD_sey
- Xfinity XR11-20 Voice Remote, firmware version 1.0.1.0



Mitigation

There is no apparent mechanism to allow Comcast customers to change this behavior.



Recommended Remediation

Use cryptographically signed firmware images that are checked on both the set-top box and remote.



Credits

Marc Newlin and Logan Lamb, Bastille
Chris Grayson, Web Sight.IO