CVE-2012-4619 in IOS
Summary
by MITRE
The NAT implementation in Cisco IOS 12.2, 12.4, and 15.0 through 15.2 allows remote attackers to cause a denial of service (device reload) via transit IP packets, aka Bug ID CSCtr46123.
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Analysis
by VulDB Data Team • 04/14/2021
The vulnerability identified as CVE-2012-4619 represents a critical flaw in Cisco IOS operating systems affecting versions 12.2, 12.4, and 15.0 through 15.2. This issue resides within the Network Address Translation implementation, specifically impacting devices that utilize NAT functionality for packet forwarding. The vulnerability manifests when the system processes transit IP packets that contain specific malformed or crafted packet structures, leading to a complete device reload and subsequent denial of service condition. This flaw demonstrates a fundamental weakness in the packet processing logic that governs how NAT devices handle incoming traffic, particularly when such traffic traverses the device without being destined for the local network.
The technical nature of this vulnerability stems from improper handling of IP packet headers during the NAT translation process, where the system fails to properly validate packet structures before attempting to perform address translation operations. When malicious actors craft IP packets with specific characteristics that exploit this validation gap, the device's NAT module encounters an error condition that triggers an automatic system reload. This behavior aligns with CWE-129, which describes improper validation of input boundaries, and specifically relates to the improper handling of network packet data structures. The vulnerability operates at the network layer, affecting the core routing and forwarding capabilities of affected Cisco devices, making it particularly dangerous in network infrastructure environments where device reliability is paramount.
The operational impact of CVE-2012-4619 extends beyond simple service disruption, as it can result in complete network outages when affected devices reload. This vulnerability is particularly concerning because it allows remote attackers to initiate denial of service attacks without requiring authentication or physical access to the device. The attack can be executed from anywhere on the internet, making it a significant threat to network availability and reliability. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to Network Denial of Service, where adversaries leverage weaknesses in network infrastructure to disrupt services. The impact cascades through network operations, potentially affecting multiple services that depend on the affected device for routing and connectivity, especially in enterprise and service provider environments where NAT functionality is extensively used.
Mitigation strategies for this vulnerability require immediate patching of affected Cisco IOS versions, with the implementation of security updates provided by Cisco through their security advisories. Organizations should prioritize applying the relevant software updates to all affected devices, as the vulnerability can be exploited remotely without authentication. Network administrators should also implement traffic filtering measures to prevent malicious IP packets from reaching vulnerable devices, particularly by configuring access control lists to drop packets with suspicious characteristics. Additionally, monitoring systems should be enhanced to detect unusual reload patterns or traffic anomalies that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining current security patches and implementing proper network segmentation to limit the potential impact of such exploits, as outlined in the NIST cybersecurity framework's continuous monitoring and vulnerability management practices.