CVE-2016-1344 in IOS XE
Summary
by MITRE
The IKEv2 implementation in Cisco IOS 15.0 through 15.6 and IOS XE 3.3 through 3.17 allows remote attackers to cause a denial of service (device reload) via fragmented packets, aka Bug ID CSCux38417.
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Analysis
by VulDB Data Team • 10/15/2024
The vulnerability described in CVE-2016-1344 represents a critical denial of service flaw within Cisco IOS and IOS XE implementations of the Internet Key Exchange version 2 protocol. This vulnerability affects a broad range of Cisco networking equipment including routers and switches running specific versions of the operating system. The issue manifests when the system processes fragmented Internet Key Exchange packets, which are commonly used in secure network communications to establish and maintain encrypted connections between network devices. The vulnerability is particularly concerning as it can be exploited remotely without requiring authentication, making it accessible to any attacker with network access to the affected device.
The technical root cause of this vulnerability stems from improper handling of fragmented IKEv2 packets within the Cisco IOS processing pipeline. When the system receives fragmented packets that are part of an IKEv2 negotiation, the implementation fails to properly validate or process the fragmentation sequence, leading to a memory corruption condition that ultimately results in a device crash and subsequent reload. This flaw specifically impacts the IKEv2 protocol stack where the device attempts to reassemble fragmented packets before processing them. The vulnerability is categorized as a buffer overflow or memory corruption issue, which is classified under CWE-129 in the Common Weakness Enumeration system. The improper handling of packet fragmentation creates a condition where the device's memory management system becomes corrupted, leading to an uncontrolled termination of the IKEv2 service and eventually a complete system reboot.
The operational impact of this vulnerability extends beyond simple service disruption as it can severely compromise network availability and reliability. Organizations relying on Cisco devices for secure communications, particularly those implementing IPsec VPN connections, face significant risk from this vulnerability. The remote exploitation capability means that attackers can trigger the denial of service from external networks, potentially disrupting critical business operations or network security infrastructure. The vulnerability affects both IOS and IOS XE platforms, which represent a substantial portion of Cisco's enterprise and service provider networking equipment. This creates widespread exposure across various network environments including corporate networks, service provider backbones, and government infrastructure where IKEv2 is commonly deployed for secure communications. The impact is particularly severe in environments where network availability is critical, as the device reload can take several minutes to complete, during which time network services are unavailable.
Mitigation strategies for this vulnerability require immediate implementation of Cisco's security advisories and patches. Organizations should prioritize updating their Cisco IOS and IOS XE devices to versions that contain the necessary fixes for the IKEv2 fragmentation handling issue. The recommended approach involves applying the latest security patches provided by Cisco through their official advisory process, which typically includes modifications to the IKEv2 packet processing logic to properly handle fragmented packets. Network administrators should also implement additional monitoring and logging to detect potential exploitation attempts, as the vulnerability may generate specific patterns of fragmented IKEv2 traffic that can serve as indicators of attack activity. Network segmentation and access control measures can provide additional protection by limiting the attack surface and preventing unauthorized access to devices that may be vulnerable. The vulnerability's classification under the ATT&CK framework for network service disruption and denial of service operations highlights the importance of implementing robust network monitoring and incident response procedures. Organizations should also consider implementing temporary workarounds such as disabling IKEv2 functionality or restricting access to affected devices until permanent patches can be deployed, ensuring that network security operations continue to maintain their integrity and availability.