CVE-1999-0441 in WinGate Proxy
Summary
by MITRE
Remote attackers can perform a denial of service in WinGate machines using a buffer overflow in the Winsock Redirector Service.
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Analysis
by VulDB Data Team • 01/21/2025
The vulnerability identified as CVE-1999-0441 represents a critical buffer overflow flaw within the Winsock Redirector Service of WinGate machines, which are widely deployed internet gateway and proxy solutions. This security weakness specifically targets the network communication layer of the WinGate software, creating a pathway for remote exploitation that can lead to complete service disruption. The vulnerability exists in the way the Winsock Redirector Service handles incoming network requests, particularly those involving socket operations that exceed predetermined buffer limits. The flaw stems from inadequate input validation and memory management practices within the service's network handling code, making it susceptible to malicious input that can overwrite adjacent memory locations.
The technical implementation of this vulnerability allows remote attackers to craft specially malformed network packets that, when processed by the vulnerable WinGate service, trigger a buffer overflow condition. This occurs because the service does not properly validate the length of incoming data before copying it into fixed-size memory buffers. When the attacker sends data exceeding the buffer capacity, the excess data overflows into adjacent memory regions, potentially corrupting critical program state information or even executing arbitrary code. The nature of this flaw makes it particularly dangerous as it can be exploited without requiring authentication or prior access to the system, enabling attackers to leverage network-based attacks against vulnerable targets.
The operational impact of CVE-1999-0441 extends beyond simple service disruption, as it can effectively render entire network gateways inoperative and compromise the integrity of the underlying network infrastructure. Organizations relying on WinGate for internet access control, proxy services, or firewall protection face significant risk when systems remain unpatched, as the vulnerability can be exploited to deny legitimate network users access to essential services. This denial of service condition can persist until the affected service is manually restarted or the system is rebooted, creating operational downtime that can span from minutes to hours depending on the organization's response time and recovery procedures. The vulnerability affects the availability aspect of the CIA triad, fundamentally undermining the reliability of network services that organizations depend upon for business continuity.
Mitigation strategies for this vulnerability should prioritize immediate patch application from the vendor, as the fix typically involves correcting the buffer handling logic within the Winsock Redirector Service to properly validate input lengths and implement proper memory boundary checks. Organizations should also consider implementing network segmentation and access controls to limit exposure of vulnerable systems to untrusted networks, while monitoring network traffic for suspicious patterns that may indicate exploitation attempts. Security teams should establish incident response procedures specifically addressing denial of service scenarios involving network infrastructure components, ensuring rapid identification and remediation of affected systems. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to critical system compromise, making it a significant target for ATT&CK technique T1499, which encompasses network denial of service attacks. Organizations should also conduct vulnerability assessments to identify other potentially vulnerable network services and implement defense-in-depth strategies to protect against similar exploitation vectors across their infrastructure.