CVE-2015-0772 in TelePresence Video Communication Server
Summary
by MITRE
Cisco TelePresence Video Communication Server (VCS) X8.5RC4 allows remote attackers to cause a denial of service (CPU consumption or device outage) via a crafted SDP parameter-negotiation request in an SDP session during a SIP connection, aka Bug ID CSCut42422.
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Analysis
by VulDB Data Team • 05/21/2022
The Cisco TelePresence Video Communication Server VCS X8.5RC4 contains a critical vulnerability that enables remote attackers to execute denial of service attacks through manipulation of Session Description Protocol parameters during SIP communication sessions. This vulnerability specifically targets the SDP parameter-negotiation process within the SIP connection lifecycle, allowing adversaries to craft malicious requests that consume excessive CPU resources or trigger complete device outages. The flaw exists in the VCS software implementation where insufficient input validation occurs during SDP session handling, creating an exploitable condition that can be leveraged from remote network locations without requiring authentication credentials. The vulnerability has been catalogued as CSCut42422 and represents a significant security risk for organizations relying on Cisco VCS for video communication infrastructure.
The technical mechanism behind this vulnerability involves the improper handling of crafted SDP parameter-negotiation requests that are transmitted as part of SIP session initiation protocols. When the VCS processes these malformed SDP messages, the system fails to properly validate or sanitize the parameter values, leading to a condition where the device becomes overwhelmed with processing demands. The vulnerability specifically affects the session description protocol parsing logic within the SIP communication stack, where the system attempts to negotiate parameters between communicating parties. Attackers can construct SDP messages containing specially crafted parameter values that cause the VCS to enter an infinite loop or consume excessive computational resources during the negotiation phase. This behavior results in either gradual CPU exhaustion that degrades system performance or complete system crash that leads to service interruption.
The operational impact of CVE-2015-0772 extends beyond simple service disruption to potentially compromise entire video communication infrastructures within affected organizations. When exploited successfully, the vulnerability can cause complete device outages that affect critical business communications, video conferencing services, and collaborative work environments that depend on Cisco VCS for their operations. The remote nature of the attack means that threat actors can exploit this vulnerability from anywhere on the internet without requiring physical access to the network or devices. Organizations utilizing the affected VCS versions may experience extended downtime during attack windows, leading to productivity losses and potential business continuity issues. The vulnerability affects the availability aspect of the CIA triad by targeting system resources and operational capabilities rather than confidentiality or integrity.
Security professionals should implement immediate mitigations including applying the relevant Cisco security patches and updates released to address this vulnerability. Network segmentation and access control measures can help limit the exposure of VCS systems to untrusted networks, while monitoring solutions should be deployed to detect anomalous SDP parameter patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how insufficient sanitization of user-supplied data can lead to resource exhaustion attacks. From an ATT&CK framework perspective, this vulnerability maps to the privilege escalation and denial of service tactics, specifically targeting the system resources and availability of network infrastructure components. Organizations should also consider implementing rate limiting and connection throttling mechanisms to prevent rapid exploitation attempts and reduce the effectiveness of automated attack tools that might target this specific vulnerability.