CVE-2012-4141 in NX-OS
Summary
by MITRE
Directory traversal vulnerability in the CLI parser in Cisco NX-OS allows local users to create arbitrary script files via a relative pathname in the "file name" parameter, aka Bug IDs CSCua71557 and CSCua71551.
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Analysis
by VulDB Data Team • 05/26/2021
The vulnerability identified as CVE-2012-4141 represents a directory traversal flaw within the Command Line Interface parser of Cisco NX-OS operating system. This security weakness affects network devices running Cisco NX-OS software, particularly those implementing the CLI functionality for system administration. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied file path parameters, creating an exploitable condition that can be leveraged by local attackers with system access.
The technical implementation of this vulnerability occurs within the CLI parser component where the system processes file name parameters without adequate path validation. When a local user submits a file name parameter containing relative path traversal sequences such as ../ or ..\, the system fails to properly resolve or sanitize these paths before executing file creation operations. This flaw specifically impacts the handling of file creation commands where the system accepts user input for file naming without proper canonicalization or path restriction checks. The vulnerability is classified under CWE-22, which represents improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks.
From an operational perspective, this vulnerability enables local attackers to potentially create arbitrary script files in unintended directories within the system filesystem. The implications extend beyond simple file creation, as these maliciously placed scripts could be executed by the system or other processes, potentially leading to privilege escalation or persistent access. Attackers could exploit this weakness to place backdoor scripts, modify system configuration files, or establish unauthorized access points within the network infrastructure. The local privilege requirement means that an attacker must already have access to the system, but this vulnerability significantly amplifies their capabilities once they have established a foothold.
The impact of this vulnerability is particularly concerning for network infrastructure devices running Cisco NX-OS, as these systems often operate with elevated privileges and contain critical network configuration data. The vulnerability affects Cisco Nexus 5000, 6000, and 7000 series switches, among other affected platforms, making it a significant concern for enterprise network security. Organizations relying on these devices for core network operations face potential exposure to attackers who could leverage this weakness to compromise network integrity and availability. The vulnerability's classification as a local privilege escalation vector means that even if initial access requires legitimate credentials, the potential for privilege elevation through script creation makes this a critical concern.
Mitigation strategies for CVE-2012-4141 should focus on implementing proper input validation and path sanitization within the CLI parser components. Network administrators should ensure that all Cisco NX-OS devices are updated with the latest security patches provided by Cisco, specifically addressing the directory traversal vulnerabilities in the CLI parser. System configurations should include restrictions on file creation operations and proper canonicalization of all path parameters before processing. The implementation of principle of least privilege and regular security audits can help detect unauthorized script creation attempts. Additionally, monitoring systems should be configured to alert on unusual file creation patterns or attempts to create scripts in sensitive directories. This vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, where adversaries use local system commands to establish persistence or escalate privileges through script execution.