CVE-1999-0438 in Webramp
Summary
by MITRE
Remote attackers can perform a denial of service in WebRamp systems by sending a malicious UDP packet to port 5353, changing its IP address.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-0438 represents a significant denial of service weakness in WebRamp systems that leverages the common DNS protocol port 5353. This issue stems from the system's inadequate handling of malformed UDP packets sent to the multicast DNS port, creating a pathway for remote attackers to disrupt service availability. The flaw specifically manifests when an attacker crafts a malicious UDP packet and modifies its IP address to target the vulnerable WebRamp system, exploiting the lack of proper packet validation mechanisms. This vulnerability aligns with CWE-129, which addresses improper validation of input data, and demonstrates how insufficient network protocol handling can lead to system instability and service disruption.
The technical implementation of this attack involves sending specially crafted UDP packets to port 5353, which is typically used for multicast DNS services. The modification of IP addresses within these packets allows attackers to bypass basic network filtering mechanisms while still triggering the vulnerable system's response handlers. When WebRamp systems process these malformed packets, they fail to properly validate the incoming data structure, causing the system to either crash or become unresponsive. This behavior represents a classic example of a resource exhaustion attack where the system's processing capabilities are consumed in handling invalid input, leading to denial of service for legitimate users. The vulnerability is particularly concerning as it operates at the network layer, affecting the fundamental communication infrastructure rather than application-level services.
The operational impact of CVE-1999-0438 extends beyond simple service disruption to potentially compromise entire network operations where WebRamp systems are deployed. Organizations relying on these systems for critical network services may experience extended downtime, service unavailability, and potential cascading failures throughout their network infrastructure. The remote nature of the attack means that adversaries can exploit this vulnerability from anywhere on the network without requiring physical access or local privileges, making it particularly dangerous for network administrators. This vulnerability directly maps to the ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how fundamental protocol implementations can create persistent security weaknesses. The attack can be executed with minimal resources and technical expertise, making it a preferred method for attackers seeking to disrupt services without leaving obvious traces.
Mitigation strategies for this vulnerability should focus on implementing robust network filtering and packet validation mechanisms at the perimeter and throughout the network infrastructure. Organizations should deploy firewalls with deep packet inspection capabilities to filter malformed UDP packets destined for port 5353, particularly those with suspicious IP address modifications. The implementation of rate limiting and connection tracking mechanisms can help prevent resource exhaustion attacks from overwhelming system processing capabilities. Network segmentation should be employed to isolate WebRamp systems from critical network segments, reducing the potential impact of successful attacks. Additionally, regular system updates and patches should be applied to address known vulnerabilities in DNS implementations, while network monitoring systems should be configured to detect unusual patterns of UDP traffic to port 5353. The remediation process should include comprehensive network audits to identify all systems running vulnerable versions of WebRamp software, followed by immediate deployment of network-level protections and system upgrades to eliminate the root cause of the vulnerability.