CVE-2008-1156 in IOS
Summary
by MITRE
Unspecified vulnerability in the Multicast Virtual Private Network (MVPN) implementation in Cisco IOS 12.0, 12.2, 12.3, and 12.4 allows remote attackers to create "extra multicast states on the core routers" via a crafted Multicast Distribution Tree (MDT) Data Join message.
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Analysis
by VulDB Data Team • 06/01/2025
The vulnerability described in CVE-2008-1156 represents a critical flaw within Cisco IOS implementations that affects multiple versions including 12.0, 12.2, 12.3, and 12.4. This issue specifically targets the Multicast Virtual Private Network functionality which is essential for efficient multicast traffic management in enterprise and service provider networks. The vulnerability exists in the core routing protocols that handle multicast distribution tree operations, creating a significant security risk for organizations relying on Cisco networking equipment for their multicast infrastructure. The flaw manifests when the system processes crafted Multicast Distribution Tree Data Join messages, which are part of the standard multicast routing protocols used to establish and maintain multicast distribution paths.
The technical nature of this vulnerability stems from insufficient validation and processing of incoming multicast messages within the Multicast Virtual Private Network implementation. When a remote attacker sends a specially crafted MDT Data Join message, the Cisco IOS software fails to properly validate the message structure and content before processing it. This lack of proper input validation allows the system to create additional multicast states in the core routers without proper authorization or security checks. The vulnerability essentially enables attackers to manipulate the multicast routing table and potentially consume excessive memory resources on core routers. According to CWE classification, this represents a weakness in input validation and resource management, specifically categorized under CWE-20 (Improper Input Validation) and CWE-400 (Uncontrolled Resource Consumption). The flaw operates at the network protocol level, affecting the fundamental routing mechanisms that govern multicast traffic flow.
The operational impact of this vulnerability extends beyond simple resource consumption, creating potential denial of service conditions and unauthorized network access. Attackers can exploit this weakness to overwhelm core routers with excessive multicast state entries, leading to performance degradation or complete service disruption. The created multicast states can persist in the router's memory, consuming valuable resources that should be available for legitimate network operations. This vulnerability particularly affects service providers and large enterprise networks that rely heavily on multicast routing for applications such as video streaming, online gaming, and collaborative applications. The remote nature of the attack means that threat actors can exploit this vulnerability from outside the network perimeter without requiring local access or authentication credentials, making it especially dangerous for public-facing network equipment.
Mitigation strategies for this vulnerability require immediate implementation of Cisco IOS patches and updates that address the multicast message validation flaws. Network administrators should implement access control lists and filtering mechanisms to restrict incoming multicast traffic from untrusted sources, particularly focusing on MDT Data Join messages. The implementation of monitoring and alerting systems that can detect unusual multicast state creation patterns provides early warning capabilities for potential exploitation attempts. Organizations should also consider implementing network segmentation strategies to limit the impact of potential exploitation and reduce the attack surface for multicast routing protocols. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving resource exhaustion and protocol manipulation, specifically mapping to T1499.004 (Endpoint Denial of Service) and T1071.004 (Application Layer Protocol: DNS). Regular network audits and vulnerability assessments should include verification of multicast routing configurations to ensure that all affected Cisco IOS versions have been properly patched and updated.