CVE-1999-0844 in MDaemon
Summary
by MITRE
Denial of service in MDaemon WorldClient and WebConfig services via a long URL.
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Analysis
by VulDB Data Team • 10/22/2025
The vulnerability described in CVE-1999-0844 represents a classic denial of service flaw affecting MDaemon WorldClient and WebConfig services. This issue manifests when malicious actors submit excessively long URLs to the affected services, causing system resources to become exhausted and ultimately leading to service disruption. The vulnerability specifically targets the URL handling mechanisms within these email server components, which fail to properly validate or limit input length during request processing. Such flaws typically arise from inadequate input validation routines that do not account for abnormal data lengths, creating opportunities for resource exhaustion attacks that can render critical email services unavailable to legitimate users.
The technical implementation of this vulnerability demonstrates a fundamental flaw in the software's request parsing logic where the system processes URL parameters without proper bounds checking. When a malformed request containing an extremely long URL is received, the MDaemon services attempt to process the entire parameter string, consuming memory resources and potentially causing stack overflow conditions. This type of vulnerability aligns with CWE-122, which describes buffer overflow conditions that occur when a program writes more data to a buffer than it can hold. The lack of input sanitization and length validation creates an exploitable condition where attackers can craft specially malformed requests to overwhelm system resources. From an operational perspective, this vulnerability represents a significant risk to email infrastructure since it can be exploited with minimal technical expertise, requiring only the ability to send HTTP requests to the vulnerable services.
The operational impact of CVE-1999-0844 extends beyond simple service disruption to encompass broader organizational consequences including email communication outages, productivity losses, and potential revenue impacts for businesses relying on MDaemon email services. Attackers can leverage this vulnerability through various methods including automated scanning tools that systematically probe for vulnerable services, or through direct exploitation using simple HTTP request construction. The vulnerability's classification under the MITRE ATT&CK framework would fall within the denial of service category, specifically targeting network service availability. Organizations utilizing MDaemon WorldClient and WebConfig services face significant exposure since these components often serve as primary interfaces for email management and configuration. The attack vector is particularly concerning because it requires minimal privileges and can be executed remotely, making it an attractive target for both opportunistic attackers and those seeking to disrupt specific organizations.
Mitigation strategies for this vulnerability encompass multiple layers of defensive measures including immediate patch application from MDaemon, implementation of input validation rules at network boundaries, and configuration changes to limit URL parameter lengths. Organizations should deploy web application firewalls or intrusion prevention systems that can detect and block malformed URL requests before they reach the vulnerable services. Network administrators must also configure rate limiting and connection timeout settings to prevent resource exhaustion attacks from overwhelming system resources. The remediation process involves updating the MDaemon software to versions that include proper input validation and length checking mechanisms. Additionally, implementing proper monitoring and logging of HTTP requests can help detect exploitation attempts and provide early warning of potential attacks. Security teams should also consider network segmentation to isolate vulnerable services and reduce the attack surface, while establishing incident response procedures that can quickly address exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other email server components and ensure comprehensive protection against similar denial of service vulnerabilities.