CVE-2009-2866 in IOS
Summary
by MITRE
Unspecified vulnerability in Cisco IOS 12.2 through 12.4 allows remote attackers to cause a denial of service (device reload) via a crafted H.323 packet, aka Bug ID CSCsz38104.
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Analysis
by VulDB Data Team • 03/30/2025
The vulnerability described in CVE-2009-2866 represents a critical denial of service weakness within Cisco IOS software versions 12.2 through 12.4 that specifically affects H.323 protocol handling. This issue manifests when the affected network devices receive maliciously crafted H.323 packets that trigger unexpected behavior in the device's processing logic, ultimately leading to complete device reload or reboot. The vulnerability operates at the network protocol level where H.323 signaling messages are improperly validated and processed, creating a condition where malformed packet structures can cause the system to enter an unstable state that requires manual intervention to recover.
The technical flaw underlying this vulnerability stems from inadequate input validation mechanisms within the H.323 implementation of Cisco IOS. When processing incoming H.323 packets, the system fails to properly sanitize or validate packet contents, allowing specially crafted payloads to exploit memory handling routines or state management functions. This weakness creates an exploitable condition where an attacker can construct packets that, when processed by the device, cause memory corruption or stack overflow conditions that lead to system instability. The vulnerability is classified as a buffer overflow or memory corruption issue that aligns with CWE-121 and CWE-125 categories, representing improper input validation that can result in arbitrary code execution or system crashes.
The operational impact of this vulnerability extends beyond simple service interruption as it can affect critical network infrastructure components that rely on H.323 for voice and video communication services. Network devices such as routers, switches, and unified communication appliances that support H.323 signaling protocols become susceptible to this attack, potentially disrupting voice over IP communications, video conferencing services, and other real-time multimedia applications. Organizations with extensive H.323 deployments face significant risk of service degradation or complete communication outages when attackers exploit this vulnerability. The attack vector is particularly concerning as it requires no authentication and can be executed from remote locations, making it an attractive target for malicious actors seeking to disrupt business operations.
Mitigation strategies for this vulnerability involve implementing immediate software patches provided by Cisco through their security advisories, specifically addressing the H.323 processing logic in affected IOS versions. Network administrators should also consider implementing access control lists to filter or drop suspicious H.323 traffic at network boundaries, particularly in environments where H.323 services are not required. The implementation of network segmentation and firewall rules to restrict H.323 traffic between trusted network zones can provide additional protection layers. Organizations should also monitor network traffic for unusual H.323 packet patterns and implement intrusion detection systems that can identify and alert on malformed H.323 packets that may indicate exploitation attempts. This vulnerability demonstrates the importance of maintaining up-to-date network device firmware and implementing robust network monitoring practices to detect and respond to potential security incidents.
The broader implications of this vulnerability align with ATT&CK tactics related to privilege escalation and denial of service operations, where attackers can leverage protocol weaknesses to gain control over network infrastructure. This particular weakness highlights the need for comprehensive security testing of network protocol implementations and proper input validation across all network services. The vulnerability also underscores the critical importance of maintaining detailed network documentation and understanding which protocols are actively in use within the network infrastructure, as unused protocols should be disabled to reduce attack surface. Organizations should implement regular vulnerability assessments and penetration testing to identify similar weaknesses in their network infrastructure that could be exploited through similar mechanisms.