CVE-2007-4291 in IOS
Summary
by MITRE
Cisco IOS 12.0 through 12.4 allows remote attackers to cause a denial of service via (1) a malformed MGCP packet, which causes a device hang, aka CSCsf08998; a malformed H.323 packet, which causes a device crash, as identified by (2) CSCsi60004 with Proxy Unregistration and (3) CSCsg70474; and a malformed Real-time Transport Protocol (RTP) packet, which causes a device crash, as identified by (4) CSCse68138, related to VOIP RTP Lib, and (5) CSCse05642, related to I/O memory corruption.
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Analysis
by VulDB Data Team • 08/11/2022
Cisco IOS versions 12.0 through 12.4 contain multiple vulnerabilities that enable remote attackers to induce denial of service conditions through malformed packet processing. These vulnerabilities specifically target the Media Gateway Control Protocol MGCP implementation, H.323 protocol handling, and Real-time Transport Protocol RTP packet processing within the voice over internet protocol infrastructure. The first vulnerability involves a malformed MGCP packet that causes device hang conditions, while the second and third vulnerabilities relate to H.323 protocol handling with proxy unregistration and general crash conditions respectively. The final two vulnerabilities target RTP packet processing with one related to VOIP RTP Library functions and another to I/O memory corruption mechanisms.
The technical flaw in these vulnerabilities stems from insufficient input validation and error handling within the IOS voice processing modules. When processing malformed packets, the system fails to properly validate packet structures and content, leading to unpredictable behavior and system instability. The MGCP vulnerability (CSCsf08998) demonstrates a classic buffer over-read condition where the device attempts to process malformed packet headers without proper bounds checking, resulting in system hang. The H.323 vulnerabilities (CSCsi60004 and CSCsg70474) indicate improper state handling during proxy unregistration processes, where malformed packets trigger memory corruption or invalid state transitions. The RTP vulnerabilities (CSCse68138 and CSCse05642) demonstrate memory corruption issues within the I/O subsystem when processing malformed RTP packet headers and payload structures.
These vulnerabilities pose significant operational impact to organizations relying on Cisco IOS for voice infrastructure. The denial of service conditions can result in complete service interruption for voice communications, affecting business continuity and mission-critical operations. The device hang condition from the MGCP vulnerability can require manual intervention and device reboot, while the crash conditions from H.323 and RTP vulnerabilities can cause complete system restarts. Organizations with large voice infrastructures may experience cascading failures affecting multiple voice channels and potentially impacting emergency services or critical communication pathways. The remote nature of these attacks means that attackers can exploit these vulnerabilities from outside the network perimeter without requiring authentication or physical access to the devices.
The vulnerabilities align with CWE categories including CWE-125 Out-of-bounds Read, CWE-129 Improper Validation of Array Index, CWE-787 Out-of-bounds Write, and CWE-20 Improper Input Validation. From an ATT&CK framework perspective, these vulnerabilities map to T1499.004 Network Denial of Service and T1595.001 Active Scanning, as attackers can remotely probe for vulnerable systems and exploit them to cause service disruption. The attack surface is particularly concerning in enterprise voice networks where multiple devices may be running vulnerable IOS versions, creating potential for widespread impact across telecommunications infrastructure. Organizations should implement network segmentation to isolate voice infrastructure, deploy intrusion detection systems to monitor for malformed packet traffic, and ensure prompt patching of affected IOS versions.
Mitigation strategies should include immediate implementation of IOS patches addressing these specific vulnerabilities, particularly for versions 12.0 through 12.4. Network administrators should configure access control lists to filter malformed packets at network boundaries, implement rate limiting for voice protocol traffic, and deploy monitoring solutions to detect abnormal packet patterns. The Cisco IOS software should be updated to versions containing fixes for CSCsf08998, CSCsi60004, CSCsg70474, CSCse68138, and CSCse05642 vulnerabilities. Additionally, organizations should establish monitoring procedures to detect potential exploitation attempts and maintain incident response protocols for rapid system recovery in case of successful attacks. Network administrators should also consider implementing redundant voice infrastructure to minimize impact from single point failures and establish automated alerting mechanisms for system instability conditions.