CVE-2011-2059 in IOS
Summary
by MITRE
The ipv6 component in Cisco IOS before 15.1(4)M1.3 allows remote attackers to conduct fingerprinting attacks and obtain potentially sensitive information about the presence of the IOS operating system via an ICMPv6 Echo Request packet containing a Hop-by-Hop (HBH) extension header (EH) with a 0x0c01050c value in the PadN option data, aka Bug ID CSCtq02219.
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Analysis
by VulDB Data Team • 01/29/2018
The vulnerability described in CVE-2011-2059 represents a significant security flaw within Cisco IOS operating systems that affects the IPv6 implementation. This issue specifically targets the handling of ICMPv6 Echo Request packets and exposes the system to fingerprinting attacks that can reveal sensitive information about the underlying operating system. The vulnerability stems from the improper processing of Hop-by-Hop extension headers within ICMPv6 packets, creating a reconnaissance vector that adversaries can exploit to gain insights into network infrastructure configurations. The flaw exists in Cisco IOS versions prior to 15.1(4)M1.3, making a substantial portion of deployed Cisco networking equipment susceptible to this type of attack.
The technical mechanism of this vulnerability involves the specific processing of Hop-by-Hop extension headers within ICMPv6 Echo Request packets. When an ICMPv6 Echo Request packet contains a Hop-by-Hop extension header with a particular 0x0c01050c value in the PadN option data, the Cisco IOS operating system responds in a manner that reveals information about its internal state and version. This response behavior creates a distinguishable pattern that can be used by attackers to identify the presence of Cisco IOS and potentially determine the specific version running on the device. The vulnerability operates at the network protocol level, specifically within the IPv6 stack implementation, making it particularly dangerous as it can be exploited without requiring authentication or privileged access to the network infrastructure.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to conduct systematic fingerprinting of network infrastructure. This reconnaissance capability allows adversaries to map network topologies and identify Cisco devices within their target environment, potentially leading to more sophisticated attacks targeting specific vulnerabilities in the identified IOS versions. The vulnerability aligns with CWE-200, which addresses information exposure, and represents a classic example of how protocol implementation flaws can create unintended information leakage channels. Network administrators may be unaware of the presence of these devices until an attacker successfully exploits this vulnerability to gather intelligence for subsequent attacks, making it particularly concerning for enterprise environments where network visibility is crucial for security operations.
The implications of this vulnerability can be severe for organizations relying on Cisco networking equipment, as it provides attackers with a low-effort method to gather intelligence about their network infrastructure. The ability to identify specific IOS versions through simple packet analysis means that attackers can tailor subsequent attacks to exploit known vulnerabilities in those particular versions. This vulnerability demonstrates the importance of proper protocol implementation and the potential risks associated with overly verbose responses to malformed network packets. Organizations should consider implementing network segmentation and monitoring to detect unusual ICMPv6 traffic patterns that might indicate fingerprinting attempts. The issue also highlights the need for regular security updates and patch management processes, as the vulnerability was addressed in Cisco IOS version 15.1(4)M1.3, representing a clear case where timely patch deployment could have prevented the exposure. From an ATT&CK framework perspective, this vulnerability maps to reconnaissance techniques that involve information gathering and fingerprinting activities, specifically targeting network infrastructure to understand the operational environment before launching more complex attacks.