CVE-2012-4135 in NX-OS
Summary
by MITRE
Directory traversal vulnerability in filesys in Cisco NX-OS 6.1(2) and earlier allows local users to access arbitrary files via crafted command-line arguments during a delete action, aka Bug IDs CSCty07270, CSCty07271, CSCty07273, and CSCty07275.
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Analysis
by VulDB Data Team • 05/18/2017
The directory traversal vulnerability identified as CVE-2012-4135 affects Cisco NX-OS versions 6.1(2) and earlier, specifically within the filesys component during delete operations. This vulnerability represents a critical security flaw that enables local attackers to bypass normal file access controls and retrieve arbitrary files from the system. The issue manifests when malicious command-line arguments are provided during file deletion processes, creating an exploitable path that allows unauthorized file access. The vulnerability was catalogued under multiple bug IDs including CSCty07270, CSCty07271, CSCty07273, and CSCty07275, indicating the complexity and widespread nature of the affected components within the network operating system. This type of vulnerability falls under the Common Weakness Enumeration category CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical implementation of this vulnerability exploits the insufficient input validation within the filesys component of Cisco NX-OS when processing delete commands. Local users can manipulate command-line arguments to traverse directory structures beyond the intended scope, potentially accessing sensitive system files, configuration data, or other restricted resources. The flaw occurs during the file deletion operation where the system fails to properly sanitize user input, allowing attackers to construct malicious paths that can bypass access controls and retrieve files that should otherwise remain protected. This vulnerability specifically targets the delete functionality, making it particularly concerning for network administrators who rely on proper file management and security controls within their network infrastructure.
The operational impact of CVE-2012-4135 extends beyond simple unauthorized file access, as it provides attackers with potential access to sensitive system information that could aid in further exploitation attempts. Network administrators managing Cisco NX-OS devices running vulnerable versions face significant risks including exposure of system configurations, user credentials, or other confidential data that could be used to compromise the entire network infrastructure. The local privilege escalation aspect of this vulnerability means that attackers with limited access to the system can potentially gain broader access to sensitive files and system resources. This vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries may use local commands to manipulate file systems and exploit path traversal flaws. The impact is particularly severe in enterprise environments where network switches and routers running affected NX-OS versions serve as critical infrastructure components.
Mitigation strategies for this vulnerability require immediate patching of affected Cisco NX-OS installations to versions that address the directory traversal flaw in the filesys component. Network administrators should implement strict access controls and monitoring for file system operations, particularly delete commands, to detect potential exploitation attempts. The recommended approach includes applying the latest security patches from Cisco, which would contain fixes for the identified directory traversal vulnerabilities. Additionally, implementing network segmentation and privilege separation can help limit the potential impact of successful exploitation attempts. Organizations should also conduct thorough vulnerability assessments to identify all affected devices and ensure that proper file access controls are in place to prevent unauthorized file access. The remediation process should include verifying that the patched versions properly address all identified bug IDs and that no residual vulnerabilities remain within the system's file handling mechanisms.