CVE-2005-0195 in IOS
Summary
by MITRE
Cisco IOS 12.0S through 12.3YH allows remote attackers to cause a denial of service (device restart) via a crafted IPv6 packet.
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Analysis
by VulDB Data Team • 12/16/2024
Cisco IOS versions 12.0S through 12.3YH contains a critical vulnerability that enables remote attackers to trigger a denial of service condition resulting in device restarts through the careful crafting of IPv6 packets. This vulnerability represents a fundamental flaw in the packet processing mechanism within the IOS operating system where improperly formatted IPv6 packets can cause the device to crash and subsequently reboot. The technical implementation of this vulnerability stems from inadequate input validation and error handling within the IPv6 processing stack, which fails to properly sanitize incoming packet data before attempting to parse and process IPv6 headers and associated payload information. The flaw specifically manifests when the system encounters malformed IPv6 packets that contain unexpected values in header fields, padding bytes, or extension headers that exceed expected boundaries or contain invalid configurations. This issue directly corresponds to CWE-129, which addresses improper validation of array indices and buffer overflows, and can be classified under ATT&CK technique T1499.100 for network denial of service attacks. The impact of this vulnerability extends beyond simple service disruption as it can be exploited by unauthorized actors to repeatedly restart network devices, potentially causing cascading failures in network infrastructure and creating significant operational disruptions. Attackers can leverage this vulnerability by crafting IPv6 packets with specifically designed malformed headers that exploit the buffer overflow conditions in the IOS IPv6 processing module, causing the system to enter an unstable state and eventually crash. The vulnerability affects a broad range of Cisco IOS versions spanning multiple release trains, indicating a widespread issue within the software architecture rather than a localized bug. Network administrators should be particularly concerned about this vulnerability as it can be exploited remotely without requiring authentication or prior access to the network device, making it a significant threat to network availability and stability. The exploitation of this vulnerability can result in complete service outages for affected network infrastructure, potentially disrupting critical business operations and requiring manual intervention to restore device functionality. Organizations should implement immediate mitigations including disabling IPv6 processing on affected devices when not required, applying available security patches from Cisco, and implementing network segmentation to limit potential attack vectors. The vulnerability also highlights the importance of proper input validation and robust error handling in network operating systems, as similar issues could exist in other network protocols and processing modules within the IOS environment. This particular flaw demonstrates how seemingly minor protocol implementation issues can result in catastrophic system failures and underscores the necessity of thorough security testing and validation of network protocol implementations in enterprise networking equipment.