CVE-2008-4444 in Unified Ip Phone 7940g
Summary
by MITRE
Cisco Unified IP Phone (aka SIP phone) 7960G and 7940G with firmware P0S3-08-9-00 and possibly other versions before 8.10 allows remote attackers to cause a denial of service (device reboot) or possibly execute arbitrary code via a Realtime Transport Protocol (RTP) packet with malformed headers.
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Analysis
by VulDB Data Team • 08/27/2019
The vulnerability described in CVE-2008-4444 represents a critical security flaw affecting Cisco Unified IP Phone models 7960G and 7940G running specific firmware versions. This vulnerability resides within the Realtime Transport Protocol implementation of these SIP phones, which are widely deployed in enterprise communication environments. The affected devices operate within the context of voice communication infrastructure, making them attractive targets for adversaries seeking to disrupt business continuity or escalate privileges within network environments.
The technical flaw manifests through improper handling of RTP packet headers during the processing of incoming media streams. When malformed RTP headers are received, the phone firmware fails to validate or sanitize these inputs properly, leading to unpredictable behavior. This vulnerability falls under the CWE-129 category of "Improper Validation of Array Index" and is closely related to CWE-125 "Out-of-bounds Read" as the malformed headers can trigger buffer overflows or memory corruption within the device's processing routines. The vulnerability specifically targets the RTP stack implementation within the phone's firmware, where insufficient input validation allows attackers to craft malicious packets that exploit memory handling deficiencies.
From an operational impact perspective, this vulnerability enables remote attackers to perform denial of service attacks by causing device reboots, effectively disrupting voice communication services for users within the affected network segments. The potential for arbitrary code execution adds another layer of severity, as successful exploitation could allow attackers to gain control over the device and potentially pivot to other network resources. The attack surface is particularly concerning because it requires no authentication, making it accessible to anyone on the network segment, and the impact extends beyond individual device compromise to potentially affect entire communication infrastructures. Organizations using these devices face significant risk of service disruption, potential data exposure, and possible escalation to broader network compromise scenarios.
Mitigation strategies for this vulnerability should include immediate firmware updates to versions 8.10 or later, which contain patches addressing the RTP header validation issues. Network segmentation and access controls should be implemented to limit exposure of these devices to untrusted network segments, while monitoring systems should be deployed to detect anomalous RTP traffic patterns. The vulnerability aligns with ATT&CK technique T1203 "Exploitation for Client Execution" and T1499 "Endpoint Termination" as it enables both arbitrary code execution and device reboot capabilities. Organizations should also implement network-based intrusion detection systems capable of identifying malformed RTP traffic and establish incident response procedures for handling potential exploitation attempts. Regular vulnerability assessments and network scanning should be conducted to identify any remaining unpatched devices within the enterprise environment.