CVE-2020-3530 in IOS XR
Summary
by MITRE
A vulnerability in task group assignment for a specific CLI command in Cisco IOS XR Software could allow an authenticated, local attacker to execute that command, even though administrative privileges should be required. The attacker must have valid credentials on the affected device. The vulnerability is due to incorrect mapping in the source code of task group assignments for a specific command. An attacker could exploit this vulnerability by issuing the command, which they should not be authorized to issue, on an affected device. A successful exploit could allow the attacker to invalidate the integrity of the disk and cause the device to restart. This vulnerability could allow a user with read permissions to issue a specific command that should require Administrator privileges.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-3530 resides within Cisco IOS XR Software, a critical networking operating system used in enterprise and service provider environments. This flaw represents a serious privilege escalation issue that undermines the software's access control mechanisms, specifically affecting how task group assignments are mapped for certain command executions. The vulnerability manifests as a flaw in the software's authorization framework where legitimate administrative commands are incorrectly mapped to less restrictive task groups, allowing unauthorized users to execute privileged operations.
The technical root cause of this vulnerability stems from improper source code implementation where the mapping between specific CLI commands and their required task groups contains a critical error. This misconfiguration allows authenticated users with minimal privileges to bypass normal access controls and execute commands that should only be available to administrators. The flaw operates at the software level where the operating system's privilege enforcement mechanisms fail to properly validate user permissions against command requirements, creating a path for unauthorized command execution.
From an operational perspective, this vulnerability presents a significant risk to network infrastructure security as it allows attackers with only read-level permissions to escalate their privileges and execute destructive commands. The potential impact includes complete system compromise, disk integrity violations, and unauthorized device restarts that could disrupt critical network services. Network administrators face the challenge of having to assume that any authenticated user could potentially exploit this vulnerability to gain unauthorized administrative access, fundamentally undermining the security model of the affected devices.
The vulnerability aligns with CWE-284, which addresses improper access control in software implementations, and represents a classic case of insufficient authorization checks. Attackers could leverage this weakness through the standard CLI interface, requiring only valid login credentials to exploit the vulnerability. This makes the attack surface particularly concerning as it doesn't require specialized tools or complex exploitation techniques beyond legitimate user access. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the 'Abuse Elevation Control Mechanisms' tactic where attackers manipulate system controls to gain higher privileges than originally granted.
Mitigation strategies should include immediate software patching through Cisco's security advisories, implementation of strict access control policies, and monitoring for unauthorized command execution attempts. Network administrators should also consider implementing additional authentication layers and regularly reviewing user permissions to minimize the impact of such vulnerabilities. The affected devices require immediate attention through official Cisco security updates to correct the task group assignment mappings and restore proper authorization controls within the IOS XR software environment.