CVE-2003-1325 in Half-Life Counter Strike Dedicated Server
Summary
by MITRE
The SV_CheckForDuplicateNames function in Valve Software Half-Life CSTRIKE Dedicated Server 1.1.1.0 and earlier allows remote authenticated users to cause a denial of service (infinite loop and daemon hang) via a certain connection string to UDP port 27015 that represents "absence of player informations," a related issue to CVE-2006-0734.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability described in CVE-2003-1325 represents a critical denial of service flaw within Valve Software's Half-Life Counter-Strike Dedicated Server version 1.1.1.0 and earlier implementations. This issue specifically targets the SV_CheckForDuplicateNames function which serves as a crucial component in managing player connections and maintaining server integrity. The flaw manifests when legitimate authenticated users submit malformed connection strings to the UDP port 27015, which typically serves as the primary communication port for game server operations. The vulnerability operates through a specific condition where the connection string contains what the exploit refers to as "absence of player informations," creating a scenario that triggers an infinite loop within the server's processing logic.
The technical execution of this vulnerability stems from inadequate input validation within the SV_CheckForDuplicateNames function, which fails to properly handle malformed or incomplete player data structures. When an authenticated user submits a connection string lacking proper player information, the function enters an infinite loop that consumes excessive CPU resources and effectively hangs the server daemon. This particular implementation flaw aligns with CWE-835, which specifically addresses infinite loops or iterations that can lead to denial of service conditions. The vulnerability demonstrates how insufficient validation of user-supplied data can create exploitable conditions that compromise system availability, particularly in networked gaming environments where server stability directly impacts player experience and game integrity.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects the fundamental availability and reliability of Counter-Strike dedicated servers. When exploited, the infinite loop causes the server daemon to become unresponsive, preventing new player connections while potentially disconnecting existing players. This creates cascading effects that can severely impact competitive gaming environments, tournament operations, and server hosting services that rely on consistent uptime. The vulnerability's classification as a related issue to CVE-2006-0734 indicates it shares underlying architectural weaknesses in how the server handles player authentication and connection management, suggesting a broader pattern of inadequate input validation across the software's networking components. Network administrators and game server operators face significant operational challenges when dealing with such vulnerabilities, as they must balance security updates with service availability.
Mitigation strategies for CVE-2003-1325 should focus on immediate patching of the affected software versions to address the specific input validation flaw in the SV_CheckForDuplicateNames function. The recommended approach involves implementing comprehensive input sanitization and validation mechanisms that properly handle edge cases and malformed data structures before they can trigger the infinite loop condition. Network-level protections such as rate limiting and connection filtering can provide additional defense in depth measures, though these should complement rather than replace proper software patching. The vulnerability also highlights the importance of implementing proper error handling and timeout mechanisms within server applications to prevent resource exhaustion attacks. Organizations should consider implementing monitoring solutions that can detect anomalous CPU usage patterns or connection behavior that may indicate exploitation attempts, aligning with ATT&CK technique T1499.200 which addresses network denial of service attacks through resource exhaustion. Regular security assessments and vulnerability scanning of gaming server environments remain essential practices for identifying and addressing similar weaknesses that could lead to service disruption in networked applications.