CVE-2009-0634 in IOS
Summary
by MITRE
Multiple unspecified vulnerabilities in the home agent (HA) implementation in the (1) Mobile IP NAT Traversal feature and (2) Mobile IPv6 subsystem in Cisco IOS 12.3 through 12.4 allow remote attackers to cause a denial of service (input queue wedge and interface outage) via an ICMP packet, aka Bug ID CSCso05337.
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Analysis
by VulDB Data Team • 08/31/2019
The vulnerability described in CVE-2009-0634 represents a critical denial of service weakness affecting Cisco IOS implementations across versions 12.3 through 12.4. This flaw manifests within two distinct but related subsystems of the mobile IP framework including the Mobile IP NAT Traversal feature and the Mobile IPv6 subsystem. The vulnerability specifically targets the home agent implementation which serves as a central component in mobile IP networks responsible for managing mobile node registration and packet forwarding. The attack vector involves specially crafted ICMP packets that exploit input queue processing weaknesses in the affected Cisco IOS versions, leading to system instability and potential network outages. This vulnerability directly impacts the reliability and availability of mobile IP services within Cisco network infrastructure, affecting organizations that rely on mobile connectivity and roaming capabilities.
The technical exploitation of this vulnerability occurs through improper handling of ICMP packets within the home agent processing logic. When the affected Cisco IOS devices receive malicious ICMP packets, the input queue processing mechanism becomes overwhelmed or enters an inconsistent state that results in a queue wedge condition. This condition prevents normal packet processing and can ultimately lead to complete interface outages within the mobile IP subsystem. The root cause lies in inadequate input validation and error handling within the mobile IP NAT Traversal feature and Mobile IPv6 implementation, where the system fails to properly sanitize or reject malformed ICMP packets that trigger the queue processing failures. The vulnerability demonstrates a classic buffer over-read or input queue manipulation issue that falls under the CWE-129 weakness category related to improper input validation and the CWE-121 category for buffer overflow conditions that can lead to denial of service scenarios.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire mobile IP infrastructure within affected networks. Organizations utilizing mobile IP services for enterprise mobility, remote access, or roaming capabilities face significant risk of service interruptions that can affect business continuity and user productivity. Network administrators may experience unexpected interface failures that require manual intervention and system restarts to restore normal operations. The vulnerability particularly affects environments where mobile IP is heavily utilized for wireless connectivity, VPN services, and remote enterprise access. The cascading effect of interface outages can propagate through the network, potentially impacting other services that depend on the affected routing and forwarding capabilities. This vulnerability also creates opportunities for attackers to perform sustained denial of service attacks that can systematically degrade network performance and availability.
Mitigation strategies for CVE-2009-0634 should prioritize immediate implementation of Cisco IOS patches and updates that address the specific input queue processing flaws within the mobile IP subsystems. Network administrators should implement ICMP filtering rules at network boundaries to prevent unauthorized ICMP packets from reaching vulnerable home agent implementations. The deployment of access control lists and packet filtering mechanisms can help reduce the attack surface by limiting ICMP traffic to only authorized sources. Organizations should also consider implementing network monitoring and alerting systems that can detect unusual queue processing patterns or interface state changes that may indicate exploitation attempts. Regular vulnerability assessments and network configuration reviews should be conducted to ensure that mobile IP features are properly secured and that the affected IOS versions have been upgraded to patched releases. The implementation of redundant home agent configurations and failover mechanisms can provide additional resilience against exploitation attempts. According to ATT&CK framework, this vulnerability aligns with T1499.004 (Network Denial of Service) and T1595.001 (Network Configuration) tactics, emphasizing the importance of both service disruption and configuration security in defending against such attacks. The vulnerability also demonstrates the importance of proper input validation and queue management as outlined in the NIST Cybersecurity Framework under the Protect function, particularly in managing system vulnerabilities and ensuring operational resilience.