CVE-2015-5190 in PCS
Summary
by MITRE
The pcsd web UI in PCS 0.9.139 and earlier allows remote authenticated users to execute arbitrary commands via "escape characters" in a URL.
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Analysis
by VulDB Data Team • 06/14/2022
The vulnerability identified as CVE-2015-5190 resides within the pcsd web user interface component of the Platform for Cluster Services (PCS) version 0.9.139 and earlier. This issue represents a critical command injection flaw that enables authenticated remote attackers to execute arbitrary system commands through carefully crafted URL parameters containing escape characters. The vulnerability specifically affects the web management interface of PCS, which is commonly used for cluster management and configuration in high-availability environments.
The technical root cause of this vulnerability stems from insufficient input validation and sanitization within the pcsd web UI component. When authenticated users submit requests containing malicious escape sequences in URL parameters, the system fails to properly sanitize these inputs before processing them. This allows attackers to inject command sequences that are then executed by the underlying system shell, effectively bypassing normal access controls and authentication mechanisms. The flaw operates at the application level and demonstrates poor input handling practices that align with CWE-77, which specifically addresses command injection vulnerabilities.
The operational impact of CVE-2015-5190 is severe and potentially catastrophic for organizations relying on PCS for cluster management. An authenticated attacker with access to the web UI can execute arbitrary commands with the privileges of the pcsd service account, which typically runs with elevated permissions necessary for cluster operations. This could lead to complete system compromise, data exfiltration, service disruption, or lateral movement within the network infrastructure. The vulnerability is particularly dangerous because it requires only authentication, making it accessible to users with legitimate access to the PCS web interface who may have been compromised or whose credentials have been stolen.
Organizations should immediately implement mitigations including updating to PCS versions 0.9.140 or later where this vulnerability has been addressed through proper input sanitization and validation. Network segmentation should be employed to limit access to the pcsd web interface to authorized personnel only, while implementing strict access controls and monitoring for unusual command execution patterns. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter, specifically noting the use of system shells for executing commands. Regular security audits should verify that all PCS components are updated and that proper input validation is implemented throughout the application stack to prevent similar vulnerabilities from emerging in other components.
Additional defensive measures include implementing web application firewalls to detect and block suspicious URL patterns containing escape characters, establishing strict monitoring for command execution events in system logs, and conducting regular penetration testing to identify potential injection points. The vulnerability highlights the importance of following secure coding practices such as those outlined in the OWASP Top Ten, particularly focusing on input validation and output encoding to prevent injection attacks. Organizations should also consider implementing principle of least privilege access controls to limit the potential impact of any successful exploitation attempts.