CVE-2001-1071 in IOS
Summary
by MITRE
Cisco IOS 12.2 and earlier running Cisco Discovery Protocol (CDP) allows remote attackers to cause a denial of service (memory consumption) via a flood of CDP neighbor announcements.
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Analysis
by VulDB Data Team • 12/15/2024
Cisco IOS versions 12.2 and earlier contain a vulnerability in the Cisco Discovery Protocol implementation that enables remote attackers to perform a denial of service attack through memory exhaustion. This flaw specifically affects the processing of CDP neighbor announcements where the device fails to properly validate incoming CDP packets, allowing malicious actors to flood the system with crafted CDP messages that consume excessive memory resources. The vulnerability stems from insufficient input validation and lack of rate limiting mechanisms within the CDP processing module, which is designed to discover neighboring Cisco devices on the network. When the system receives a high volume of malformed or excessive CDP neighbor announcements, it continuously allocates memory to process these packets without adequate cleanup or throttling, leading to progressive memory depletion that eventually results in system instability and denial of service conditions.
The technical exploitation of this vulnerability leverages the fundamental design flaw in how Cisco IOS handles CDP protocol messages, particularly the neighbor announcement packets that contain device information and network topology data. Attackers can send numerous forged CDP packets with varying parameters to overwhelm the device's memory management system, causing it to consume all available memory resources and potentially crash the routing process or become unresponsive. This vulnerability is categorized under CWE-129 as improper validation of length of input data, specifically manifesting as insufficient input validation within network protocol processing components. The attack vector is remote and does not require authentication, making it particularly dangerous as it can be exploited from any location on the network where CDP is enabled and accessible.
The operational impact of CVE-2001-1071 extends beyond simple service disruption to potentially compromise network availability and reliability across affected Cisco devices. When a router or switch becomes overwhelmed with CDP traffic, it may experience complete service interruption, preventing legitimate network operations from functioning properly. This can result in network segmentation issues, routing failures, and extended downtime while administrators must identify and resolve the memory exhaustion problem. The vulnerability affects critical network infrastructure components that rely on CDP for network discovery and management, making it a significant concern for enterprise networks where these devices form the backbone of network connectivity. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 for network denial of service and T1071.004 for application layer protocol usage, representing how attackers can leverage network protocol weaknesses to achieve their objectives.
Mitigation strategies for this vulnerability should focus on implementing proper network segmentation to limit CDP exposure to trusted networks while enabling rate limiting and packet filtering on affected devices. Cisco recommends disabling CDP on interfaces that do not require network discovery functionality, which reduces the attack surface significantly. Network administrators should also implement monitoring solutions to detect unusual CDP traffic patterns that may indicate exploitation attempts. The most effective long-term solution involves upgrading to Cisco IOS versions that contain patches addressing the CDP processing flaw, as these updates include proper input validation and memory management improvements. Additionally, implementing network access control lists and firewall rules to restrict CDP traffic from untrusted sources can provide additional protection layers. Organizations should also consider implementing intrusion detection systems that can identify and alert on abnormal CDP traffic patterns, enabling proactive response to potential exploitation attempts.