CVE-2016-6381 in IOS
Summary
by MITRE
Cisco IOS 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.18 and 16.1 allow remote attackers to cause a denial of service (memory consumption or device reload) via fragmented IKEv1 packets, aka Bug ID CSCuy47382.
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Analysis
by VulDB Data Team • 09/25/2024
Cisco IOS devices running versions 12.4 and 15.0 through 15.6, as well as IOS XE 3.1 through 3.18 and 16.1, contain a critical vulnerability that enables remote attackers to execute denial of service attacks through carefully crafted fragmented Internet Key Exchange version 1 packets. This vulnerability represents a memory management flaw that occurs when the device processes malformed IKEv1 fragments, leading to excessive memory consumption or complete device reloads. The issue stems from inadequate input validation and processing of fragmented IKE packets within the IOS kernel, where the system fails to properly handle the fragmentation logic during IKE negotiation processes. The vulnerability is categorized under CWE-129 as an improper input validation issue, specifically manifesting as a buffer over-read condition when processing fragmented packets. From an operational perspective, this vulnerability creates a significant risk for network infrastructure security, as attackers can exploit it remotely without authentication to disrupt network services. The attack vector involves sending specifically crafted fragmented IKEv1 packets to the target device, which then consumes excessive memory resources or triggers a system reload. This behavior directly impacts the availability aspect of the CIA triad and can result in extended network outages, particularly affecting VPN services and secure remote access capabilities. The vulnerability affects devices that support IKEv1 protocol implementations, including routers and switches that may be configured for IPsec VPN services or other security protocols relying on IKE for key exchange. The memory consumption aspect of the vulnerability can lead to gradual degradation of device performance before eventual system reload, while the immediate reload impact creates more severe service disruption. Network administrators should consider this vulnerability in the context of the MITRE ATT&CK framework, specifically under the T1499 technique for network disruption and T1072 for software deployment. The flaw demonstrates a classic example of a resource exhaustion attack pattern that can be amplified through automated scanning tools. Organizations using affected Cisco IOS versions should prioritize patching and implementation of network segmentation to limit potential attack surface. The vulnerability impacts both traditional IOS and IOS XE implementations, making it particularly concerning for organizations with hybrid network environments. Device monitoring should include memory utilization tracking and system reload detection to identify potential exploitation attempts. The vulnerability's remote execution capability means that attackers can target devices from outside the network perimeter, making it a high-priority security concern for enterprise networks relying on Cisco equipment for secure communications. Proper input validation and robust error handling mechanisms within the IKE processing code would have prevented this vulnerability from manifesting as a memory consumption issue. The flaw represents a design weakness in the packet processing logic that should have been addressed through proper bounds checking and memory management procedures.