CVE-2017-6719 in IOS XR
Summary
by MITRE
A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands on the host operating system with root privileges, aka Command Injection. More Information: CSCvb99406. Known Affected Releases: 6.2.1.BASE. Known Fixed Releases: 6.2.1.28i.BASE 6.2.1.22i.BASE 6.1.32.8i.BASE 6.1.31.3i.BASE 6.1.3.10i.BASE.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/29/2020
The vulnerability identified as CVE-2017-6719 represents a critical command injection flaw within the Command Line Interface of Cisco IOS XR Software, a widely deployed network operating system for service provider routers and switches. This vulnerability specifically affects the privileged command execution mechanisms within the CLI environment, creating a pathway for authenticated local attackers to escalate their privileges and execute arbitrary code with root-level access. The flaw exists in the software's handling of command parsing and execution within the host operating system, allowing malicious input to be interpreted and executed as system commands rather than being properly sanitized or validated. The vulnerability is particularly concerning because it requires only local authentication to exploit, meaning that any user with legitimate access to the device's CLI can potentially leverage this weakness to gain complete system control.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the CLI processing pipeline of the IOS XR software. When legitimate users execute commands through the CLI interface, the system fails to properly isolate or escape command parameters, allowing specially crafted input to be interpreted by the underlying operating system shell. This creates a classic command injection scenario where attacker-controlled data flows directly into system command execution contexts without proper boundary checking or parameter validation. The vulnerability manifests when authenticated users submit command sequences that contain malicious payloads, which are then processed through the vulnerable command parsing logic and executed with the privileges of the root user account. This type of flaw is categorized under CWE-77 as Command Injection, which is a well-documented weakness in software systems where untrusted data is incorporated into command execution contexts without proper validation or sanitization. The vulnerability's impact is amplified by the fact that it operates at the system level, bypassing traditional application-level security controls and directly accessing the host operating system capabilities.
The operational implications of CVE-2017-6719 are severe for network infrastructure deployments that rely on Cisco IOS XR Software, as it provides a direct path to complete system compromise for any authenticated local user. Attackers can leverage this vulnerability to escalate privileges from standard user accounts to root access, enabling them to modify system configurations, install malicious software, access sensitive data, and potentially establish persistent backdoors within the network infrastructure. The vulnerability affects critical network devices including service provider routers, core switches, and aggregation devices that form the backbone of telecommunications networks, making it particularly dangerous for large-scale deployments. Organizations with multiple devices running the vulnerable software versions face significant risk of coordinated attacks that could compromise entire network segments. The attack surface is further expanded by the fact that the vulnerability can be exploited through normal CLI operations, making detection difficult and potentially allowing attackers to remain undetected while maintaining persistent access to network infrastructure.
Mitigation strategies for CVE-2017-6719 primarily focus on applying the vendor-provided security patches and updates that address the command injection flaw in the IOS XR software CLI. Cisco has released specific fixed versions including 6.2.1.28i.BASE, 6.2.1.22i.BASE, 6.1.32.8i.BASE, 6.1.31.3i.BASE, and 6.1.3.10i.BASE, which contain the necessary code modifications to properly validate and sanitize command inputs within the CLI interface. Network administrators should prioritize the deployment of these patches across all affected devices in their infrastructure, particularly those handling sensitive network operations or serving as core routing points. Additional defensive measures include implementing strict access controls to limit local CLI access to only authorized personnel, monitoring CLI sessions for suspicious command patterns, and establishing robust network segmentation to contain potential compromise. From an operational security perspective, organizations should conduct comprehensive vulnerability assessments to identify all devices running the affected software versions and develop incident response procedures specifically addressing command injection vulnerabilities. The mitigation approach aligns with ATT&CK framework tactics such as privilege escalation and defense evasion, emphasizing the need for layered security controls that address both the immediate vulnerability and broader security posture of network infrastructure. Regular security monitoring and patch management processes should be strengthened to prevent similar vulnerabilities from remaining unaddressed in future deployments.