CVE-2019-12709 in IOS XR
Summary
by MITRE
A vulnerability in a CLI command related to the virtualization manager (VMAN) in Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an authenticated, local attacker to execute arbitrary commands on the underlying Linux operating system with root privileges. The vulnerability is due to insufficient validation of arguments passed to a specific VMAN CLI command on an affected device. An attacker who has valid administrator access to an affected device could exploit this vulnerability by including malicious input as the argument of an affected command. A successful exploit could allow the attacker to run arbitrary commands on the underlying operating system with root privileges, which may lead to complete system compromise.
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Analysis
by VulDB Data Team • 12/28/2023
The vulnerability identified as CVE-2019-12709 represents a critical privilege escalation flaw within Cisco IOS XR Software running on ASR 9000 Series Aggregation Services Routers. This issue specifically targets the Virtualization Manager (VMAN) component and demonstrates a classic command injection vulnerability that enables authenticated local attackers to gain root-level access to the underlying Linux operating system. The vulnerability exists in the command-line interface implementation where insufficient input validation occurs during processing of VMAN CLI commands, creating an attack surface that directly compromises the device's security posture.
The technical flaw manifests through inadequate argument validation within the VMAN CLI command processing mechanism, which falls under CWE-77 and CWE-89 categories as it involves improper validation of command arguments that can lead to arbitrary code execution. When an authenticated administrator executes a specific VMAN command with maliciously crafted arguments, the system fails to properly sanitize or validate the input before passing it to the underlying operating system shell. This vulnerability operates at the intersection of privilege escalation and command injection, where legitimate administrative access becomes a vector for unauthorized system compromise. The flaw essentially allows attackers to bypass normal access controls and execute arbitrary commands with the highest possible privileges, effectively neutralizing the device's security boundaries.
The operational impact of this vulnerability is severe and encompasses complete system compromise, as demonstrated by the ability to execute arbitrary commands with root privileges. Attackers exploiting this vulnerability can potentially access sensitive configuration data, modify system files, install malicious software, or establish persistent backdoors within the network infrastructure. This represents a significant threat to network security as it undermines the trust model of the router's administrative interface, which is typically considered a secure entry point for legitimate maintenance operations. The vulnerability's exploitation requires only valid administrator credentials, making it particularly dangerous as it leverages legitimate access privileges to achieve unauthorized system control.
Organizations should implement immediate mitigations including applying the latest security patches provided by Cisco, which address the input validation issues within the VMAN CLI processing. Network segmentation and least privilege access controls should be enforced to limit the scope of potential exploitation, while monitoring systems should be configured to detect anomalous CLI command usage patterns. The vulnerability's characteristics align with ATT&CK technique T1059.001 for command and script injection, and T1068 for exploit for privilege escalation, highlighting the need for comprehensive defensive measures. Additionally, regular security assessments and input validation reviews should be conducted to identify similar vulnerabilities in other CLI components, as this flaw demonstrates how insufficient input sanitization in administrative interfaces can create critical security risks.