CVE-2015-4685 in RealPresence Resource Manager
Summary
by MITRE
Polycom RealPresence Resource Manager (aka RPRM) before 8.4 allows local users with access to the plcm account to gain privileges via a script in /var/polycom/cma/upgrade/scripts, related to a sudo misconfiguration.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2015-4685 affects Polycom RealPresence Resource Manager version 8.3 and earlier, representing a critical privilege escalation flaw within the system's access control mechanisms. This issue specifically targets the plcm account, which serves as the primary user account for managing the Polycom Resource Manager services. The vulnerability stems from a misconfiguration in the sudoers file that grants the plcm user elevated privileges without proper restrictions or validation mechanisms.
The technical exploitation of this vulnerability occurs through a carefully crafted script located in the /var/polycom/cma/upgrade/scripts directory, which is part of the upgrade process for the Polycom Resource Manager system. This script executes with elevated privileges due to the improper sudo configuration that allows the plcm user to execute commands as root without proper authentication or command restrictions. The flaw represents a classic case of insufficient privilege separation, where a local user account with limited access can escalate to full administrative privileges through a misconfigured privilege escalation mechanism.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it creates a persistent backdoor for attackers who gain access to the plcm account. Once exploited, the attacker can execute arbitrary commands with root privileges, potentially leading to complete system compromise, data exfiltration, and unauthorized access to network resources. The vulnerability is particularly concerning because it requires minimal access to exploit, as the plcm account is typically necessary for legitimate system maintenance operations, making it a common target for attackers who seek to maintain persistent access to the system.
This vulnerability aligns with CWE-276, which describes improper privilege management in software systems, and demonstrates how weak access control mechanisms can lead to privilege escalation attacks. From an ATT&CK framework perspective, this represents a privilege escalation technique through misconfiguration, specifically targeting the T1068 privilege escalation tactic. The attack chain involves gaining initial access to the plcm account, typically through legitimate administrative access or through credential compromise, followed by exploitation of the sudo misconfiguration to achieve root privileges.
The mitigation strategy for this vulnerability requires immediate implementation of proper sudoers configuration that restricts the commands the plcm account can execute with elevated privileges. System administrators should review and tighten the sudoers file to ensure that only explicitly authorized commands can be executed with root privileges. Additionally, the upgrade process scripts should be secured with proper file permissions and ownership settings to prevent unauthorized modification. The recommended solution involves updating to Polycom RealPresence Resource Manager version 8.4 or later, which contains the patched sudo configuration that prevents unauthorized privilege escalation through the affected script. Regular security audits should be conducted to verify that similar misconfigurations do not exist in other system components, and access controls should be continuously monitored to ensure proper privilege separation is maintained throughout the system infrastructure.