CVE-2017-6728 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 code at the root privilege level on an affected system, because of Incorrect Permissions. More Information: CSCvb99389. Known Affected Releases: 6.2.1.BASE. Known Fixed Releases: 6.3.1.15i.BASE 6.2.3.1i.BASE 6.2.2.15i.BASE 6.1.4.10i.BASE.
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Analysis
by VulDB Data Team • 12/31/2020
The vulnerability identified as CVE-2017-6728 represents a critical privilege escalation flaw within Cisco IOS XR Software command line interface implementation. This security weakness stems from improper permission handling that allows authenticated local users to gain root-level system access. The vulnerability specifically affects the CLI component of IOS XR software, which serves as the primary interface for system administration and configuration tasks. Attackers exploiting this flaw can execute arbitrary code with the highest possible system privileges, effectively compromising the entire network device. The issue manifests due to inadequate access control mechanisms within the software's authentication framework, creating a pathway for malicious actors to elevate their privileges beyond normal operational boundaries.
The technical exploitation of this vulnerability occurs through a flaw in the permission model implementation within the CLI subsystem. When an authenticated user interacts with specific CLI commands, the system fails to properly validate whether the requesting user possesses adequate privileges for the intended operation. This incorrect permission handling creates a privilege escalation vector that allows local attackers to execute commands with root-level privileges. The vulnerability's impact is particularly severe because it requires only local authentication credentials rather than remote access, making it accessible to anyone with legitimate administrative access to the device. The flaw essentially bypasses the normal privilege separation mechanisms that should prevent standard users from executing administrative commands.
The operational consequences of CVE-2017-6728 extend far beyond simple privilege escalation, potentially enabling complete system compromise and unauthorized access to sensitive network infrastructure. An attacker with root-level access can modify system configurations, install malicious software, monitor network traffic, and exfiltrate confidential data. This vulnerability directly impacts network availability and integrity, as compromised devices can be used to launch further attacks against other network segments or serve as persistent backdoors. The affected releases include version 6.2.1.BASE and various other versions within the 6.2.x and 6.1.x release lines, making it a widespread issue across multiple generations of Cisco IOS XR software. Organizations running these vulnerable versions face significant risk to their network security posture, particularly in environments where privileged access is not adequately restricted.
Cisco has addressed this vulnerability through multiple software releases including 6.3.1.15i.BASE, 6.2.3.1i.BASE, 6.2.2.15i.BASE, and 6.1.4.10i.BASE. The recommended mitigation strategy involves immediate deployment of these patched versions across all affected network devices. Network administrators should conduct thorough vulnerability assessments to identify all instances of the vulnerable software and implement the necessary updates. Additionally, organizations should review and strengthen their local access controls, implement multi-factor authentication for administrative access, and establish robust monitoring procedures to detect unauthorized privilege escalation attempts. The vulnerability aligns with CWE-276, which addresses incorrect permissions in software implementations, and represents a significant concern under the ATT&CK framework's privilege escalation techniques. Organizations should also consider implementing network segmentation and access control policies to limit the potential impact of such vulnerabilities, as the ability to execute arbitrary code with root privileges creates a complete compromise scenario.