CVE-2012-4076 in NX-OS
Summary
by MITRE
Cisco NX-OS allows local users to gain privileges and execute arbitrary commands via shell metacharacters in a command that calls the system library function, aka Bug IDs CSCtf23559 and CSCtf27780.
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Analysis
by VulDB Data Team • 08/26/2017
Cisco NX-OS contains a local privilege escalation vulnerability that stems from improper handling of shell metacharacters within command execution contexts. This flaw exists in the system library function that processes user commands, creating an environment where maliciously crafted input can be interpreted as shell commands rather than simple arguments. The vulnerability specifically affects the NX-OS operating system used in Cisco's network switching and routing platforms, which are critical infrastructure components in enterprise and data center environments.
The technical implementation of this vulnerability involves the improper sanitization of input parameters when invoking system library functions that execute shell commands. When local users submit commands containing shell metacharacters such as semicolons, pipes, or backticks, these characters are not properly escaped or filtered before being passed to underlying system functions. This creates a command injection scenario where the operating system interprets the injected metacharacters as shell operators, allowing attackers to execute arbitrary commands with elevated privileges. The vulnerability is particularly dangerous because it leverages legitimate system functionality to achieve unauthorized privilege escalation.
The operational impact of this vulnerability is severe for organizations relying on Cisco NX-OS devices, as it enables local attackers with basic user access to escalate their privileges to root level. Once escalated, attackers can execute arbitrary code, modify system configurations, access sensitive network data, and potentially establish persistent backdoors within the network infrastructure. This vulnerability directly impacts the integrity and availability of network services, as compromised devices can be used to launch further attacks, disrupt network operations, or serve as pivot points for lateral movement within the network. The affected devices include various Cisco Nexus series switches and routers that utilize the NX-OS operating system.
Mitigation strategies for this vulnerability should include immediate patching of affected Cisco NX-OS versions through official Cisco security advisories and updates. Organizations should also implement strict input validation mechanisms and sanitize all user-supplied data before processing. Network segmentation and least privilege access controls can help limit the potential impact of exploitation. Security monitoring should focus on detecting unusual command execution patterns and privilege escalation attempts. This vulnerability aligns with CWE-77 and CWE-78 categories related to command injection and improper input sanitization, and maps to ATT&CK techniques such as privilege escalation through command injection and execution of malicious code. Organizations should also consider implementing network access controls and monitoring for suspicious shell metacharacter usage patterns to detect potential exploitation attempts.