CVE-2017-12331 in NX-OS
Summary
by MITRE
A vulnerability in Cisco NX-OS System Software could allow an authenticated, local attacker to bypass signature verification when loading a software patch. The vulnerability is due to insufficient NX-OS signature verification for software patches. An authenticated, local attacker could exploit this vulnerability to bypass signature verification and load a crafted, unsigned software patch on a targeted device. The attacker would need valid administrator credentials to perform this exploit. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Unified Computing System Manager. Cisco Bug IDs: CSCvf16494, CSCvf23655.
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Analysis
by VulDB Data Team • 01/25/2021
The vulnerability identified as CVE-2017-12331 represents a critical security flaw in Cisco NX-OS System Software that undermines the integrity verification mechanisms designed to protect network infrastructure devices. This weakness specifically targets the software patch loading process within Cisco's enterprise switching platforms, creating a pathway for authenticated attackers to circumvent the signature verification procedures that are fundamental to maintaining system security. The vulnerability resides in the insufficient validation mechanisms that should ensure only properly signed and verified software updates can be installed on affected systems, thereby compromising the software supply chain integrity.
The technical exploitation of this vulnerability requires an attacker to possess valid administrator credentials, establishing a local privilege requirement that limits the attack surface but does not eliminate the risk entirely. Once authenticated, the attacker can manipulate the patch loading process to bypass the signature verification checks, enabling them to install malicious or unauthorized software patches on the targeted devices. This flaw directly impacts the trust model of the NX-OS system, where the integrity of software updates is paramount to maintaining network security posture. The vulnerability affects multiple high-end Cisco networking products including the Multilayer Director Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, and Unified Computing System Manager, indicating a widespread impact across Cisco's enterprise networking portfolio.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security architecture of affected network devices. An attacker who successfully exploits this vulnerability could potentially install malicious code that remains undetected by standard security monitoring systems, as the malicious patch would appear to be a legitimate update. This capability creates opportunities for persistent threats to establish footholds within network infrastructure, potentially enabling more sophisticated attacks such as lateral movement, data exfiltration, or network disruption. The vulnerability's impact is particularly concerning given that these affected devices typically serve as core network infrastructure components that are critical to enterprise operations and network connectivity.
Organizations affected by this vulnerability should implement immediate mitigations including strengthening access controls to ensure only authorized personnel can access administrative functions, implementing strict patch management procedures with comprehensive verification steps, and monitoring for unauthorized software installations on affected systems. The vulnerability aligns with CWE-315 which addresses the exposure of sensitive information in software, and relates to ATT&CK techniques involving privilege escalation and defense evasion through legitimate system tools. Network administrators should also consider implementing additional security monitoring to detect anomalous patch installation activities and ensure that all software updates are properly verified through multiple independent validation mechanisms before deployment. The Cisco Bug IDs CSCvf16494 and CSCvf23655 indicate that this vulnerability was formally recognized and documented by Cisco, emphasizing the importance of applying the vendor-provided security patches as soon as possible to remediate the flaw.