CVE-2021-37739 in ClearPass Policy Manager
Summary
by MITRE • 10/15/2021
A remote arbitrary command execution vulnerability was discovered in Aruba ClearPass Policy Manager version(s): ClearPass Policy Manager 6.10.x prior to 6.10.2 - - ClearPass Policy Manager 6.9.x prior to 6.9.7-HF1 - - ClearPass Policy Manager 6.8.x prior to 6.8.9-HF1. Aruba has released patches for ClearPass Policy Manager that address this security vulnerability.
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Analysis
by VulDB Data Team • 10/20/2021
The vulnerability CVE-2021-37739 represents a critical remote arbitrary command execution flaw in Aruba ClearPass Policy Manager software across multiple version branches including 6.10.x before 6.10.2, 6.9.x before 6.9.7-HF1, and 6.8.x before 6.8.9-HF1. This vulnerability falls under the CWE-77 attack pattern category, specifically classified as command injection, where an attacker can execute arbitrary commands on the target system through unvalidated input processing. The affected ClearPass Policy Manager serves as a network access control solution that manages authentication, authorization, and accounting services for enterprise networks, making it a prime target for attackers seeking persistent access to critical infrastructure.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the web application interface of ClearPass Policy Manager. Attackers can exploit this weakness by crafting malicious payloads that bypass authentication mechanisms and directly inject operating system commands into vulnerable parameters. The vulnerability is particularly dangerous because it allows remote execution without requiring authentication, making it accessible to any attacker who can reach the affected system over the network. This flaw typically manifests when the application processes user-supplied data through command-line interfaces without proper sanitization, creating an attack surface where malicious input can be interpreted and executed as legitimate system commands.
The operational impact of CVE-2021-37739 extends beyond simple unauthorized code execution to encompass complete system compromise and potential lateral movement within enterprise networks. Organizations utilizing ClearPass Policy Manager as their primary network access control solution face significant risk of unauthorized access to network resources, including potential privilege escalation to system administrator level access. Attackers could leverage this vulnerability to establish persistent backdoors, exfiltrate sensitive network credentials, or deploy additional malware within the environment. The vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter, and T1078.004 for valid accounts, as it enables attackers to execute commands using legitimate system interfaces while potentially leveraging compromised credentials.
Organizations should immediately implement mitigations including applying the vendor patches released by Aruba for versions 6.10.2, 6.9.7-HF1, and 6.8.9-HF1, which address the input validation deficiencies in the affected software components. Network segmentation and firewall rules should be implemented to restrict access to ClearPass Policy Manager interfaces, particularly limiting exposure to untrusted networks. Additional protective measures include implementing web application firewalls to monitor and filter suspicious command injection attempts, enabling comprehensive logging and monitoring for anomalous command execution patterns, and conducting thorough network scans to identify any potential exploitation attempts. Security teams should also consider implementing zero-trust network access principles and regularly reviewing access controls to minimize the potential impact of any successful exploitation attempts.