CVE-2003-0260 in Vpn 30xx Concentrator
Summary
by MITRE
Cisco VPN 3000 series concentrators and Cisco VPN 3002 Hardware Client 2.x.x through 3.6.7A allow remote attackers to cause a denial of service (slowdown and possibly reload) via a flood of malformed ICMP packets.
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Analysis
by VulDB Data Team • 01/21/2025
The vulnerability identified as CVE-2003-0260 affects Cisco VPN 3000 series concentrators and Cisco VPN 3002 Hardware Client versions 2.x.x through 3.6.7A, representing a significant security weakness in network infrastructure devices that handle virtual private network connections. This flaw manifests as a denial of service condition that can severely impact network availability and performance for legitimate users. The vulnerability specifically targets the handling of Internet Control Message Protocol packets, which are fundamental components of internet communication used for error reporting and network diagnostics. The affected devices fail to properly validate incoming ICMP traffic, creating an exploitable condition that allows remote attackers to disrupt normal operations through crafted packet flooding attacks.
The technical implementation of this vulnerability stems from inadequate input validation within the ICMP processing modules of the affected Cisco devices. When these systems receive malformed ICMP packets, they do not properly sanitize or reject the malformed data before processing it, leading to resource exhaustion or system instability. This weakness can be categorized under CWE-129, which addresses insufficient input validation, and more specifically aligns with CWE-20, representing input validation issues that can lead to various security consequences including denial of service. The attack vector operates entirely over the network without requiring authentication, making it particularly dangerous as any remote attacker can exploit this condition to disrupt services. The vulnerability can cause progressive system slowdowns that may eventually lead to complete system reloads, effectively denying legitimate network access to users who depend on the VPN services.
From an operational impact perspective, this vulnerability poses a severe threat to enterprise network availability and business continuity. Organizations relying on Cisco VPN 3000 series concentrators for remote access and site-to-site connections face potential disruptions that can affect thousands of users simultaneously. The denial of service condition can result in extended downtime for critical business applications and services that depend on secure network connectivity. Network administrators may experience difficulty in diagnosing the root cause of service degradation, as the symptoms manifest as general performance issues rather than specific error conditions. This vulnerability particularly affects organizations with remote work capabilities or those requiring secure connectivity between geographically dispersed locations. The attack can be executed with minimal resources, making it accessible to a wide range of threat actors from casual attackers to more sophisticated adversaries.
The mitigation strategies for CVE-2003-0260 should include immediate implementation of network access control measures to filter ICMP traffic at network boundaries and within the affected devices themselves. Organizations should apply the relevant Cisco security patches and firmware updates that address the ICMP validation issues in the affected systems. Network administrators should implement rate limiting and traffic filtering mechanisms to prevent ICMP packet floods from overwhelming the VPN concentrators. The implementation of intrusion detection systems that can identify and block malformed ICMP traffic patterns provides an additional layer of protection. Organizations should also consider configuring the affected devices to disable unnecessary ICMP processing functions when they are not required for network operations. According to ATT&CK framework, this vulnerability maps to T1499.004, which covers network disruption attacks, and T1595.001, representing reconnaissance techniques used to identify network infrastructure weaknesses. Regular network monitoring and baseline performance measurements help establish normal operational parameters that can quickly identify when this vulnerability is being exploited, enabling rapid response to potential attacks.