CVE-2015-4328 in TelePresence Video Communication Server
Summary
by MITRE
Cisco TelePresence Video Communication Server (VCS) Expressway X8.5.2 improperly checks for a user account's read-only attribute, which allows remote authenticated users to execute arbitrary OS commands via crafted HTTP requests, as demonstrated by read or write operations on the Unified Communications lookup page, aka Bug ID CSCuv12552.
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Analysis
by VulDB Data Team • 06/12/2022
The vulnerability identified as CVE-2015-4328 affects Cisco TelePresence Video Communication Server (VCS) Expressway version 8.5.2, representing a critical authorization flaw that undermines the system's security model. This issue stems from improper validation of user account attributes, specifically the read-only flag that should prevent certain operations. The vulnerability operates within the context of a web-based management interface where authenticated users can manipulate HTTP request parameters to bypass intended access controls. The flaw manifests when users attempt to perform operations through the Unified Communications lookup page, which serves as an entry point for various administrative functions.
The technical implementation of this vulnerability involves a failure in input validation and access control mechanisms within the VCS Expressway's web server component. When authenticated users submit crafted HTTP requests containing malicious parameters, the system fails to properly verify whether the user account possesses the necessary privileges for read or write operations. This misconfiguration allows attackers to escalate privileges and execute arbitrary operating system commands on the underlying system. The vulnerability specifically targets the read-only attribute checking mechanism, which should prevent unauthorized modifications but instead permits command execution through manipulated HTTP parameters. The flaw exists in the web interface layer where user requests are processed and validated, creating a path for remote code execution through legitimate administrative functions.
The operational impact of CVE-2015-4328 extends beyond simple privilege escalation, as it provides attackers with full control over the affected VCS Expressway system. Remote authenticated users can leverage this vulnerability to execute arbitrary OS commands, potentially leading to complete system compromise, data exfiltration, and disruption of video communication services. The attack vector requires only authentication credentials, making it particularly dangerous as it can be exploited by insiders or compromised accounts. The vulnerability affects the core functionality of the video communication infrastructure, potentially disrupting business continuity and communication services. Organizations relying on Cisco VCS Expressway for critical video conferencing operations face significant risk of service interruption and unauthorized access to their communication networks.
Mitigation strategies for CVE-2015-4328 should prioritize immediate patching of affected systems with Cisco's security updates and firmware releases. Network segmentation and access control measures can help limit the impact of potential exploitation by restricting access to the vulnerable web interface. Implementing additional authentication controls such as multi-factor authentication and monitoring for suspicious HTTP request patterns can provide defense-in-depth protection. Organizations should also conduct comprehensive security assessments of their video communication infrastructure and review user access permissions to ensure least privilege principles are enforced. The vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and maps to ATT&CK technique T1059 for command and scripting interpreter, as the vulnerability enables execution of arbitrary operating system commands through the web interface.
This vulnerability demonstrates the critical importance of proper access control implementation in networked systems and highlights the risks associated with insufficient input validation in web applications. The flaw represents a classic case of privilege escalation through improper attribute checking, where the system fails to properly validate user permissions before executing administrative operations. Organizations should implement regular security assessments and vulnerability scanning to identify similar authorization flaws in their network infrastructure. The incident underscores the need for robust security testing practices, particularly in mission-critical communication systems where unauthorized access can have significant operational and security implications. Proper configuration management and regular security updates remain essential defenses against such vulnerabilities that can compromise entire communication infrastructures.