CVE-2017-12301 in NX-OS
Summary
by MITRE
A vulnerability in the Python scripting subsystem of Cisco NX-OS Software could allow an authenticated, local attacker to escape the Python parser and gain unauthorized access to the underlying operating system of the device. The vulnerability exists due to insufficient sanitization of user-supplied parameters that are passed to certain Python functions within the scripting sandbox of the affected device. An attacker could exploit this vulnerability to escape the scripting sandbox and execute arbitrary commands on the underlying operating system with the privileges of the authenticated user. To exploit this vulnerability, an attacker must have local access and be authenticated to the targeted device with administrative or Python execution privileges. These requirements could limit the possibility of a successful exploit. This vulnerability affects the following Cisco products if they are running Cisco NX-OS Software: Multilayer Director Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches - Standalone, NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules. Cisco Bug IDs: CSCvb86832, CSCvd86474, CSCvd86479, CSCvd86484, CSCvd86490, CSCve97102, CSCvf12757, CSCvf12804, CSCvf12815, CSCvf15198.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 01/19/2021
This vulnerability represents a critical sandbox escape flaw in Cisco NX-OS Software's Python scripting subsystem that demonstrates a fundamental failure in input validation and privilege separation. The weakness stems from inadequate sanitization of user-supplied parameters passed to Python functions within the scripting environment, creating a pathway for authenticated local attackers to bypass security boundaries. The vulnerability specifically targets the Python parser's handling of parameters, allowing malicious input to traverse the sandbox mechanism and gain access to underlying operating system resources. This type of vulnerability is classified as a code injection flaw that directly violates the principle of least privilege and sandbox isolation, where the Python execution environment should remain strictly contained and isolated from the host operating system.
The technical exploitation of CVE-2017-12301 requires an attacker to possess local administrative access or Python execution privileges on the target device, which significantly limits the attack surface but does not eliminate the risk entirely. The vulnerability's impact extends across multiple Cisco networking platforms including various Nexus series switches and fabric modules, indicating a widespread exposure that affects enterprise network infrastructure. Attackers can leverage this flaw to execute arbitrary commands with the privileges of the authenticated user, potentially escalating to full system compromise depending on the user's access level. The vulnerability's exploitation path involves passing specially crafted parameters through Python functions that should have been properly sanitized, creating a direct execution channel from the scripting layer to the operating system kernel.
The operational impact of this vulnerability is substantial for enterprise network security, as it provides a means for insider threats or compromised accounts to gain elevated privileges and potentially access sensitive network infrastructure. The affected devices represent critical network components that often handle core routing, switching, and network management functions, making successful exploitation particularly dangerous. Organizations running these Cisco products face potential data exfiltration, network disruption, and unauthorized access to network resources. The vulnerability's persistence across multiple product lines and software versions indicates a systemic issue in the Python sandbox implementation that requires comprehensive remediation rather than isolated patching.
Mitigation strategies should focus on immediate patch deployment through official Cisco security advisories and firmware updates addressing the specific sanitization issues in the Python subsystem. Network administrators should implement strict access controls and privilege separation to minimize the impact of potential exploitation, ensuring that only authorized personnel have administrative or Python execution privileges. The vulnerability highlights the importance of proper input validation and sandbox isolation as outlined in CWE-77 and CWE-78, which address code injection and privilege escalation flaws respectively. Additionally, monitoring for unusual Python script execution patterns and command-line activity should be implemented to detect potential exploitation attempts, aligning with ATT&CK technique T1059.006 for command and scripting interpreter. Organizations should also consider implementing network segmentation and monitoring to detect lateral movement attempts that might occur following successful exploitation of this vulnerability.