CVE-2013-5565 in IOS XR
Summary
by MITRE
The OSPFv3 functionality in Cisco IOS XR 5.1 allows remote attackers to cause a denial of service (process crash) via a malformed LSA Type-1 packet, aka Bug ID CSCuj82176.
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Analysis
by VulDB Data Team • 06/01/2021
The vulnerability described in CVE-2013-5565 represents a critical denial of service flaw within Cisco IOS XR 51 operating system version that specifically affects the OSPFv3 routing protocol implementation. This issue manifests through the improper handling of malformed Link State Advertisement packets, particularly LSA Type-1 packets which are fundamental components of the OSPFv3 protocol used for exchanging network topology information between routers. The flaw exists in the routing process execution engine where the system fails to properly validate incoming packet structures before processing them, creating a condition where maliciously crafted packets can trigger unexpected behavior in the routing daemon.
The technical nature of this vulnerability stems from inadequate input validation mechanisms within the OSPFv3 implementation, which falls under CWE-20 - Improper Input Validation. When a remote attacker sends a specially crafted LSA Type-1 packet with malformed fields or unexpected data structures, the IOS XR router's OSPFv3 process encounters a buffer overflow or memory corruption condition that results in an immediate process crash. This occurs because the system lacks proper bounds checking and error handling routines to gracefully manage unexpected packet formats, causing the routing protocol daemon to terminate unexpectedly and disrupting network connectivity for affected devices.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the core routing functionality of network infrastructure. When the OSPFv3 process crashes, routers lose their ability to maintain accurate routing tables and communicate with neighboring devices, potentially causing widespread network partitioning and routing instability across the affected network segments. Network administrators may experience significant downtime as the system requires manual intervention to restart the crashed processes and re-establish proper routing convergence. The vulnerability is particularly concerning in production environments where high availability and network stability are critical requirements, as a single malicious packet can compromise the routing integrity of an entire network domain.
Mitigation strategies for this vulnerability require immediate implementation of network segmentation and access control measures to limit exposure to untrusted networks. Organizations should deploy ingress filtering mechanisms to block malformed OSPFv3 packets at network boundaries, particularly focusing on LSA Type-1 packet validation rules. Cisco recommends upgrading to IOS XR 52 or later versions where the vulnerability has been patched through enhanced input validation routines and improved error handling mechanisms. Network administrators should also implement monitoring solutions to detect unusual OSPFv3 packet patterns and establish automated alerting systems to identify potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004 - Endpoint Denial of Service, where adversaries leverage protocol implementation flaws to disrupt network services, making it essential for security teams to implement both preventive and detective controls to protect against such attacks.