CVE-2017-9497 in MX011ANM
Summary
by MITRE
The Comcast firmware on Motorola MX011ANM (firmware version MX011AN_2.9p6s1_PROD_sey) devices allows physically proximate attackers to execute arbitrary commands as root by pulling up the diagnostics menu on the set-top box, and then posting to a Web Inspector route.
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Analysis
by VulDB Data Team • 11/02/2019
This vulnerability resides in the Comcast firmware running on Motorola MX011ANM set-top boxes, specifically affecting firmware version MX011AN_2.9p6s1_PROD_sey. The flaw represents a critical security weakness that allows attackers with physical proximity to the device to escalate privileges and execute arbitrary commands with root-level access. The vulnerability exploits the device's diagnostics interface, which is designed for legitimate troubleshooting purposes but contains insecure implementation that bypasses normal authentication mechanisms. Attackers can access this privileged interface by manipulating the set-top box's diagnostics menu and then leveraging a Web Inspector route to gain root execution privileges.
The technical implementation of this vulnerability stems from inadequate input validation and privilege separation within the device's web interface components. When the diagnostics menu is accessed, the system fails to properly validate user input or enforce proper access controls for the Web Inspector functionality. This design flaw falls under CWE-284, which addresses improper access control, and specifically relates to CWE-749, which covers exposed dangerous methods or functions. The vulnerability demonstrates poor security architecture where administrative functions remain accessible without proper authentication mechanisms, creating an attack surface that should be restricted to authorized personnel only.
The operational impact of this vulnerability is severe given the physical proximity requirement for exploitation, which means attackers must be within the device's immediate vicinity to carry out the attack. This constraint limits the attack vector but does not eliminate the risk, as physical access to set-top boxes is common in residential and commercial environments. The root access granted by this vulnerability allows attackers to completely compromise the device, potentially enabling them to modify firmware, install backdoors, monitor network traffic, or use the device as a pivot point for attacking other networked systems. The attack chain typically involves accessing the diagnostics menu through physical interaction with the device, followed by exploiting the Web Inspector route to gain root privileges, which aligns with techniques described in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation.
Mitigation strategies for this vulnerability require both immediate firmware updates and operational security measures. Device manufacturers should implement proper input validation for all web interface components and enforce strict access controls for diagnostic and administrative functions. The firmware should be updated to disable or properly secure the Web Inspector route and ensure that access to diagnostics menus requires proper authentication credentials. Network segmentation and monitoring should be implemented to detect unusual access patterns or command execution attempts. Additionally, physical security measures such as securing device locations and implementing access controls for set-top boxes can help reduce the attack surface. Organizations should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts and establish incident response procedures for handling compromised devices. The vulnerability highlights the importance of securing all interface components within embedded systems and demonstrates how seemingly legitimate diagnostic features can become attack vectors when not properly secured.