CVE-2017-12341 in NX-OS
Summary
by MITRE
A vulnerability in the CLI of Cisco NX-OS System Software could allow an authenticated, local attacker to perform a command injection attack. An attacker would need valid administrator credentials to perform this exploit. The vulnerability is due to insufficient input validation during the installation of a software patch. An attacker could exploit this vulnerability by installing a crafted patch image with the vulnerable operation occurring prior to patch activation. An exploit could allow the attacker to execute arbitrary commands on an affected system as root. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 2000 Series Fabric Extenders, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Unified Computing System Manager. Cisco Bug IDs: CSCvf23735, CSCvg04072.
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Analysis
by VulDB Data Team • 01/25/2021
This vulnerability resides within the command line interface of Cisco NX-OS System Software, representing a critical authentication bypass and command injection flaw that enables local attackers with administrative privileges to execute arbitrary code with root-level permissions. The vulnerability specifically manifests during the software patch installation process where inadequate input validation permits malicious payloads to be embedded within patch images. The flaw stems from insufficient sanitization of user-supplied data during patch processing, creating an environment where crafted inputs can be interpreted as executable commands rather than benign configuration parameters.
The technical exploitation occurs through a carefully constructed patch image that contains malicious command sequences which are executed during the pre-activation phase of patch installation. This timing is crucial as it allows the attacker to inject commands before the patch becomes active, effectively bypassing normal operational controls and security mechanisms. The vulnerability affects a broad range of Cisco networking equipment including high-end switches and unified computing systems, making it particularly dangerous in enterprise environments where these devices serve as critical network infrastructure components.
From an operational perspective, this vulnerability represents a severe threat to network security as it allows attackers with legitimate administrative credentials to escalate privileges and execute arbitrary commands on affected systems. The impact extends beyond simple command execution to potentially enable full system compromise, data exfiltration, and network disruption. Attackers could leverage this vulnerability to establish persistent access, modify network configurations, or use the compromised systems as launch points for further attacks within the network infrastructure. The vulnerability's presence across multiple product lines including the Nexus 7000 and 7700 Series Switches, which are typically deployed in core network infrastructure, amplifies the potential damage.
Security professionals should implement immediate mitigations including restricting administrative access to only trusted personnel, implementing strict patch management procedures with thorough validation before deployment, and monitoring for unusual patch installation activities. The vulnerability aligns with CWE-77 and CWE-94 categories related to command injection and code execution flaws, and maps to ATT&CK techniques involving privilege escalation and command execution. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation and establish robust audit trails to detect unauthorized administrative activities. The affected products require urgent patch deployment to address the input validation deficiencies and prevent exploitation by malicious actors.