CVE-2002-2379 in IOS
Summary
by MITRE
** DISPUTED ** Cisco AS5350 IOS 12.2(11)T with access control lists (ACLs) applied and possibly with ssh running allows remote attackers to cause a denial of service (crash) via a port scan, possibly due to an ssh bug. NOTE: this issue could not be reproduced by the vendor.
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Analysis
by VulDB Data Team • 09/04/2024
The vulnerability described in CVE-2002-2379 relates to a potential denial of service condition affecting Cisco AS5350 routers operating with IOS version 12.2(11)T. This issue becomes particularly concerning when access control lists are actively configured on the device and Secure Shell protocol is enabled for remote management. The vulnerability manifests when remote attackers execute port scanning activities against the affected router, potentially causing the device to crash or become unresponsive. The reported behavior suggests that the interaction between the access control lists and the SSH implementation creates a condition where legitimate network scanning activities can trigger system instability.
The technical mechanism behind this vulnerability appears to involve the interaction between the router's packet processing engine and its SSH daemon when handling incoming network traffic. When ACLs are applied to interfaces, they create specific filtering rules that govern traffic flow, but in combination with SSH functionality, certain packet patterns generated during port scanning can cause unexpected behavior in the router's processing pipeline. This could potentially lead to buffer overflows, memory corruption, or other internal state inconsistencies that result in system crashes. The vulnerability specifically targets the router's ability to maintain stable operation under normal network conditions while processing legitimate security scanning activities.
From an operational perspective, this vulnerability presents a significant risk to network infrastructure reliability and availability. Network administrators who rely on Cisco AS5350 routers for core network services could face unexpected outages when attackers perform routine port scanning activities. The impact extends beyond simple service disruption as the router crash could potentially interrupt network connectivity for multiple users or services depending on the router's role in the network topology. The fact that this vulnerability specifically affects systems with both ACLs and SSH running indicates that organizations with security-conscious configurations may be particularly vulnerable, as these are common security practices that would typically be implemented in production environments.
The disputed nature of this vulnerability, as noted in the description, stems from the vendor's inability to reproduce the issue in their testing environment. This characteristic makes the vulnerability particularly challenging to address definitively, as security teams cannot confirm the exact conditions required to trigger the exploit. However, the potential exists for attackers to leverage this condition to disrupt network services, making proactive mitigation strategies essential regardless of the ability to reproduce the specific behavior. Organizations should consider implementing additional network segmentation measures, monitoring for unusual scanning patterns, and maintaining updated firmware versions to address potential variations of this vulnerability.
Security professionals should approach this vulnerability with caution given its disputed status while maintaining awareness of potential impacts. The vulnerability aligns with common attack patterns documented in the attack lifecycle where initial reconnaissance activities can lead to system compromise. Network defenders should consider this in their threat modeling exercises and ensure that their monitoring systems can detect unusual patterns of network scanning that might trigger such conditions. The potential for this vulnerability to be exploited during network reconnaissance phases makes it particularly relevant to organizations that maintain strict security policies and conduct regular network scanning activities. Proper incident response procedures should include preparation for potential router crashes and recovery strategies that account for this specific denial of service condition.