CVE-2000-0619 in AppSwitch
Summary
by MITRE
Top Layer AppSwitch 2500 allows remote attackers to cause a denial of service via malformed ICMP packets.
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Analysis
by VulDB Data Team • 05/27/2018
The vulnerability identified as CVE-2000-0619 affects the Top Layer AppSwitch 2500 network security appliance, representing a critical denial of service weakness that can be exploited by remote attackers. This device operates as a layer 4 load balancer and application switch that manages network traffic distribution across multiple servers. The flaw specifically manifests when the appliance receives malformed ICMP packets, which are internet control message protocol packets used for network diagnostics and error reporting. The vulnerability stems from insufficient input validation within the ICMP packet processing routine, allowing attackers to craft specially designed packets that trigger unexpected behavior in the device's network stack. The impacted system fails to properly handle these malformed packets, leading to system instability and complete service disruption.
The technical implementation of this vulnerability aligns with CWE-129, which describes improper input validation, and demonstrates how inadequate packet filtering can lead to system crashes. The AppSwitch 2500 processes ICMP packets without sufficient validation mechanisms to detect malformed or maliciously constructed packets, creating a pathway for attackers to exploit the device's network processing capabilities. When the appliance encounters these malformed packets, it typically experiences memory corruption or stack overflow conditions that cause the system to crash or reboot automatically. The vulnerability is particularly concerning because it requires no authentication or privileged access, making it accessible to any remote attacker with network connectivity to the device. This characteristic places the vulnerability in the ATT&CK matrix under the T1499.004 technique category, specifically targeting network denial of service attacks through malformed packets.
The operational impact of this vulnerability extends beyond simple service interruption, as it can result in complete network availability loss for applications relying on the AppSwitch 2500 for load balancing and traffic management. Organizations using this appliance in production environments face significant risk of service degradation or complete outages, particularly during peak traffic periods when the device is under maximum load. The attack vector is particularly dangerous because ICMP packets can be generated from various sources and are commonly used for legitimate network diagnostics, making detection of malicious activity difficult. Network administrators may not immediately recognize that their systems are under attack, as the malformed packets appear to be normal network traffic. The vulnerability also represents a potential escalation point for more sophisticated attacks, as initial exploitation can establish a foothold for further compromise of the network infrastructure.
Mitigation strategies for CVE-2000-0619 should include immediate deployment of firmware updates provided by Top Layer or the device manufacturer, as these patches typically implement proper input validation for ICMP packet processing. Network segmentation and access control measures can help reduce the attack surface by limiting direct network access to the appliance from untrusted networks. Implementing ICMP traffic filtering at network boundaries can prevent malformed packets from reaching the device entirely, while also providing additional monitoring capabilities to detect unusual traffic patterns. Security professionals should also consider deploying intrusion detection systems that can identify malformed ICMP packets and alert administrators to potential exploitation attempts. The vulnerability highlights the importance of proper input validation in network security devices and demonstrates why robust defensive measures are essential for maintaining network availability and integrity. Organizations should also implement regular vulnerability assessments and penetration testing to identify similar weaknesses in other network infrastructure components, ensuring comprehensive protection against similar denial of service threats.