CVE-2014-0684 in NX-OS
Summary
by MITRE
Cisco NX-OS 6.2(2) on Nexus 7000 switches allows local users to cause a denial of service via crafted sed input, aka Bug ID CSCui56136.
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Analysis
by VulDB Data Team • 05/31/2017
The vulnerability identified as CVE-2014-0684 affects Cisco NX-OS software version 6.2(2) running on Nexus 7000 series switches, representing a significant local privilege escalation and denial of service weakness. This issue stems from improper input validation within the system's sed command processing functionality, which creates a path for malicious local users to exploit the switch's operational capabilities. The vulnerability specifically manifests when the system processes crafted sed input commands, leading to unpredictable behavior that can ultimately result in complete system service disruption.
The technical flaw resides in the insufficient sanitization and validation of input parameters passed to the sed utility within the NX-OS environment. When local users submit maliciously crafted sed commands, the system fails to properly validate the input structure, allowing arbitrary command execution patterns to be interpreted and processed. This input handling weakness creates a condition where the system's command processing engine becomes susceptible to malformed input sequences that can trigger buffer overflows, memory corruption, or other exploitable states. The vulnerability operates at the system level where user input directly influences the execution flow of critical system utilities, making it particularly dangerous for network infrastructure devices.
From an operational impact perspective, this vulnerability presents a severe risk to network availability and stability since the Nexus 7000 series switches serve as core infrastructure components in enterprise and data center environments. A successful exploitation can result in complete denial of service conditions where the switch becomes unresponsive or requires manual intervention to restore functionality. Network administrators face the challenge of potential extended outages when local users, either accidentally or maliciously, trigger this condition. The impact extends beyond immediate service disruption to include potential data loss, configuration corruption, and extended recovery periods that can affect business continuity and network operations.
The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-20, which covers input validation weaknesses. From an ATT&CK framework perspective, this represents a privilege escalation technique under T1068, where local users leverage system weaknesses to gain elevated privileges and cause system instability. The attack vector requires local access to the device, making it less likely to be exploited remotely but still dangerous within compromised network environments where attackers have already gained system-level access. Organizations should consider implementing access controls, monitoring for unusual command execution patterns, and maintaining up-to-date firmware to mitigate this vulnerability. The recommended mitigation involves applying Cisco's security patches and updates that address the input validation flaws in the sed command processing functionality, along with implementing proper access controls to limit local user privileges on critical network infrastructure devices.