CVE-2017-9498 in MX011ANM
Summary
by MITRE
The Comcast firmware on Motorola MX011ANM (firmware version MX011AN_2.9p6s1_PROD_sey) and Xfinity XR11-20 Voice Remote devices allows local users to upload arbitrary firmware images to an XR11 by leveraging root access. In other words, there is no protection mechanism involving digital signatures for the firmware.
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Analysis
by VulDB Data Team • 11/02/2019
The vulnerability identified as CVE-2017-9498 affects Comcast's firmware implementation on Motorola MX011ANM and Xfinity XR11-20 Voice Remote devices, representing a critical security flaw in the firmware update mechanism. This issue stems from the complete absence of digital signature verification during firmware installation processes, creating a fundamental weakness that allows unauthorized firmware modifications. The vulnerability specifically impacts devices running firmware version MX011AN_2.9p6s1_PROD_sey, where the lack of authentication mechanisms enables local attackers with root access to upload arbitrary firmware images without proper validation. This flaw fundamentally undermines the device's security posture by eliminating the cryptographic protection that would normally prevent unauthorized firmware modifications. The absence of digital signature verification creates a pathway for malicious actors to install compromised firmware versions that could potentially provide persistent backdoor access or disable security features entirely.
The technical implementation of this vulnerability resides in the firmware update subsystem's design, which fails to enforce cryptographic integrity checks during the flashing process. According to CWE-311, this represents a missing cryptographic protection mechanism where the device lacks proper verification of firmware authenticity. The vulnerability allows for arbitrary code execution through firmware manipulation, which directly aligns with ATT&CK technique T1059.001 for command and scripting interpreter execution and T1068 for exploit for privilege escalation. The device's failure to implement proper firmware authentication creates a persistent security risk that can be exploited by attackers who gain local access to the device. The root access requirement for exploitation indicates that the vulnerability is not directly exploitable from external networks but can be leveraged by attackers who have already compromised the device's local environment or have physical access to the hardware.
The operational impact of this vulnerability extends beyond simple firmware modification capabilities, as it enables attackers to potentially install malicious firmware that could persist across device reboots and survive standard security measures. This creates a significant risk for network infrastructure devices where these voice remotes might be used as part of larger IoT ecosystems. The lack of firmware integrity checking means that any malicious firmware could potentially disable security features, modify network configurations, or provide unauthorized access to device functions. Organizations relying on these devices for voice communication or home automation services face potential risks including eavesdropping, denial of service, or complete device compromise. The vulnerability also affects the broader security model of the device, as it undermines trust in the device's software integrity and could potentially enable more sophisticated attacks that exploit the compromised firmware to gain additional privileges or access to connected systems.
Mitigation strategies for CVE-2017-9498 should focus on implementing proper firmware authentication mechanisms and ensuring that all firmware updates undergo cryptographic verification before installation. Device manufacturers should enforce digital signature validation for all firmware images and implement secure boot processes that verify firmware integrity. Network administrators should consider disabling firmware update capabilities on affected devices until proper security measures are implemented. The vulnerability highlights the importance of implementing proper firmware security practices as outlined in NIST SP 800-148, which emphasizes the need for secure firmware development and deployment practices. Organizations should also consider implementing network segmentation and monitoring to detect unauthorized firmware modifications. Additionally, the device firmware should be updated to versions that include proper digital signature verification mechanisms, and regular security assessments should be conducted to identify similar vulnerabilities in other IoT devices within the network infrastructure.