CVE-2012-4617 in IOS
Summary
by MITRE
The BGP implementation in Cisco IOS 15.2, IOS XE 3.5.xS before 3.5.2S, and IOS XR 4.1.0 through 4.2.2 allows remote attackers to cause a denial of service (multiple connection resets) by leveraging a peer relationship and sending a malformed attribute, aka Bug IDs CSCtt35379, CSCty58300, CSCtz63248, and CSCtz62914.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability described in CVE-2012-4617 represents a critical denial of service weakness within Cisco's Border Gateway Protocol implementation across multiple IOS versions. This flaw specifically affects the BGP routing protocol implementation in Cisco IOS 15.2, IOS XE 3.5.xS versions prior to 3.5.2S, and IOS XR 4.1.0 through 4.2.2 releases. The vulnerability stems from inadequate input validation mechanisms within the BGP attribute processing subsystem, where the system fails to properly handle malformed BGP attributes received from neighboring peers. This weakness creates a condition where remote attackers can exploit the protocol implementation to trigger multiple connection resets, effectively disrupting network routing operations and potentially causing widespread service degradation.
The technical exploitation of this vulnerability occurs through the manipulation of BGP attribute data during peer relationship establishment or maintenance. When a malicious actor sends specifically crafted malformed attributes to a vulnerable Cisco device, the system's BGP implementation encounters an unhandled exception or buffer overflow condition within its attribute parsing logic. This processing failure results in the immediate termination of BGP sessions with neighboring peers, causing connection resets that can cascade through the routing infrastructure. The vulnerability operates at the protocol level rather than at the application or network layer, making it particularly dangerous as it can affect the core routing functionality that maintains network connectivity. The specific bug identifiers CSCtt35379, CSCty58300, CSCtz63248, and CSCtz62914 correspond to various aspects of the same underlying implementation flaw, each representing different manifestation points within the BGP attribute processing pipeline.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network stability and availability. When multiple BGP sessions are reset simultaneously across interconnected networks, the resulting routing flapping can cause significant network instability, leading to packet loss, increased latency, and potential routing loops. Network operators may experience difficulty in maintaining consistent routing information, particularly in large enterprise or service provider environments where BGP is critical for inter-domain communication. The vulnerability's remote nature means that attackers can exploit it from outside the network perimeter, making it particularly dangerous for publicly accessible routers. Additionally, the cascading effect of connection resets can cause downstream impacts on other network services that depend on stable routing information, potentially leading to broader service degradation beyond the immediate affected devices.
Cisco addressed this vulnerability through software updates and patches released as part of their regular security advisory process. Network administrators should prioritize updating affected devices to versions containing the fix, which typically includes enhanced input validation and proper error handling for malformed BGP attributes. The mitigation strategy should also include implementing BGP monitoring and alerting mechanisms to detect unusual connection reset patterns that may indicate exploitation attempts. From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and relates to ATT&CK technique T1498, specifically focusing on network denial of service attacks. Organizations should also consider implementing network segmentation and access controls to limit exposure of critical BGP routers to untrusted networks, while maintaining detailed logging of BGP session activities for forensic analysis and threat detection purposes.