CVE-2008-0528 in Skinny Client Control Protocol
Summary
by MITRE
Buffer overflow in Cisco Unified IP Phone 7940, 7940G, 7960, and 7960G running SIP firmware might allow remote attackers to execute arbitrary code via a SIP message with crafted MIME data.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/05/2019
The vulnerability identified as CVE-2008-0528 represents a critical buffer overflow flaw affecting Cisco Unified IP Phone models 7940, 7940G, 7960, and 7960G when operating with SIP firmware. This security weakness resides in the phone's handling of SIP (Session Initiation Protocol) messages, specifically when processing crafted MIME data within these communications. The flaw stems from insufficient input validation mechanisms that fail to properly sanitize or limit the size of incoming MIME content, creating an exploitable condition where malicious actors can manipulate the device's memory structure.
The technical implementation of this vulnerability occurs during the parsing of SIP messages that contain specially crafted MIME data payloads. When the affected Cisco IP phones receive such malformed messages, the buffer overflow condition manifests as the system attempts to copy excessive data into a fixed-size memory buffer without proper bounds checking. This memory corruption can overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical execution data structures. The flaw operates at the application layer of the network stack, specifically within the SIP message processing component that handles multimedia content associated with voice communication sessions.
From an operational perspective, this vulnerability presents a significant risk to enterprise communication infrastructures since the affected phones are commonly deployed in business environments where they serve as primary communication endpoints. Remote attackers can exploit this condition without requiring physical access or authentication credentials, making the attack surface particularly concerning for organizations with network-accessible IP phone systems. The successful exploitation could result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the affected phone's operating system, potentially enabling persistent access, data exfiltration, or further network reconnaissance activities.
The impact of this vulnerability extends beyond individual device compromise to potentially affect entire communication networks, as these phones often serve as critical components in unified communications systems. Organizations may experience service disruption, unauthorized access to sensitive voice communications, and potential lateral movement within the network if attackers establish footholds through compromised endpoints. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of unsafe memory handling practices that violate secure coding principles. Additionally, this flaw can be categorized under ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would likely enable attackers to execute code on the compromised device.
Mitigation strategies for CVE-2008-0528 should prioritize immediate firmware updates from Cisco, as the company typically provides security patches addressing such vulnerabilities. Network segmentation and access controls should be implemented to limit exposure of IP phone systems to untrusted networks, while implementing SIP message filtering at network boundaries to prevent malformed traffic from reaching affected devices. Organizations should also consider disabling unnecessary SIP features and implementing monitoring solutions to detect anomalous SIP traffic patterns that might indicate exploitation attempts. Regular security assessments of unified communications infrastructure, including vulnerability scanning of IP phone systems, should be conducted to identify and remediate similar vulnerabilities in related network components.