CVE-2012-4075 in NX-OS
Summary
by MITRE
Cisco NX-OS allows local users to gain privileges and execute arbitrary commands via shell metacharacters in unspecified command parameters, aka Bug IDs CSCtf19827 and CSCtf27788.
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Analysis
by VulDB Data Team • 05/15/2017
This vulnerability exists within Cisco NX-OS operating system software running on network switches and routers, representing a critical privilege escalation flaw that enables local attackers to execute arbitrary code with elevated privileges. The vulnerability stems from improper input validation mechanisms within the command processing subsystem where shell metacharacters are not adequately sanitized or escaped when processing user-supplied parameters. Attackers can exploit this weakness by crafting malicious command inputs containing special shell characters such as semicolons, ampersands, or backticks that get interpreted by the underlying shell during command execution, thereby bypassing normal access controls and privilege boundaries.
The technical implementation of this vulnerability involves the manipulation of command parameters through shell metacharacters that allow attackers to inject additional commands into the execution flow. When the NX-OS system processes these malformed inputs, the shell interprets the injected commands as legitimate operations, effectively granting the attacker root-level privileges. This flaw operates at the operating system level within the NX-OS environment, making it particularly dangerous as it can be exploited by any user with local access to the device, whether through console, SSH, or Telnet connections. The vulnerability demonstrates characteristics consistent with CWE-78 Improper Neutralization of Special Elements used in an OS Command, which specifically addresses the improper handling of shell metacharacters in command execution contexts.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the network device, enabling them to modify routing tables, disable security features, redirect traffic, or establish persistence mechanisms. Network administrators face significant risk since local access to these devices is often required for maintenance operations, making the attack surface larger than initially apparent. The vulnerability affects multiple Cisco NX-OS versions and hardware platforms, complicating remediation efforts across enterprise networks where these devices are commonly deployed for core switching and routing functions. This weakness can be leveraged by attackers who gain physical access to the device or who have already compromised other network components to reach the target system.
Mitigation strategies for this vulnerability require immediate patching of affected NX-OS versions through official Cisco security advisories and updates. Network administrators should implement the principle of least privilege by restricting local access to network devices and employing strong authentication mechanisms. Additionally, monitoring systems should be configured to detect unusual command execution patterns that might indicate exploitation attempts. The vulnerability aligns with several ATT&CK techniques including privilege escalation through command injection and persistence mechanisms, making it a significant concern for security operations centers that must account for both internal and external threat actors who might exploit this weakness. Organizations should also consider implementing network segmentation and access controls to limit potential lateral movement if devices become compromised, while maintaining detailed audit logs of all command execution activities for forensic analysis purposes.