CVE-2004-1207 in Serious Engine
Summary
by MITRE
The Serious engine, as used in (1) Alpha Black Zero Intrepid Protocol 1.04 and earlier, (2) Nitro family, and (3) Serious Sam Second Encounter 1.07 allows remote attackers to cause a denial of service (server crash) via a large number of UDP join requests that exceeds the maximum player limit, as originally reported for Alpha Black Zero.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability described in CVE-2004-1207 affects the Serious engine, a game engine used in several popular titles including Alpha Black Zero Intrepid Protocol 1.04 and earlier versions, Nitro family games, and Serious Sam Second Encounter 1.07. This represents a classic denial of service vulnerability that exploits the engine's handling of network connections and player management systems. The vulnerability specifically targets the UDP join request mechanism that servers use to manage player connections and maintain their player count limits. The flaw demonstrates a fundamental weakness in the engine's resource management and connection handling protocols, where the system fails to properly validate or rate-limit incoming connection requests.
The technical implementation of this vulnerability involves exploiting the engine's failure to properly enforce player limits during the connection establishment phase. When remote attackers flood the server with an excessive number of UDP join requests that exceed the maximum player capacity, the Serious engine's connection handling logic becomes overwhelmed and eventually crashes the server. This occurs because the engine does not implement adequate rate limiting or connection validation mechanisms to prevent such resource exhaustion attacks. The vulnerability operates at the network protocol level, specifically targeting the user datagram protocol implementation within the game engine's networking stack. The attack vector is particularly effective because UDP is connectionless and the engine does not adequately verify the legitimacy or rate of incoming connection requests, making it susceptible to simple flood attacks that can be executed with minimal resources.
The operational impact of this vulnerability extends beyond simple server downtime, as it can severely disrupt gameplay experiences for legitimate users and potentially affect server availability for entire gaming communities. When a server crashes due to this vulnerability, all players currently connected to that server lose their session, requiring them to reconnect and potentially lose progress in ongoing games. This vulnerability particularly affects multiplayer gaming environments where server stability is critical for maintaining competitive gameplay and community engagement. The attack can be executed by anyone with access to network tools capable of sending UDP packets, making it an easily exploitable weakness that can be leveraged by malicious actors to disrupt gaming services. This type of vulnerability represents a significant concern for game developers and server administrators who must maintain service availability for their user base.
The vulnerability aligns with CWE-400, which covers "Uncontrolled Resource Consumption," as the engine fails to properly manage system resources during connection handling. It also relates to ATT&CK technique T1499.004, "Endpoint Denial of Service," since it specifically targets endpoint services to cause denial of service conditions. Mitigation strategies should focus on implementing proper rate limiting and connection validation mechanisms within the engine's networking stack. Server administrators should consider implementing network-level rate limiting to prevent excessive UDP join requests from overwhelming server resources. The most effective long-term solution involves updating to versions of the Serious engine that properly implement connection validation and resource management controls. Additionally, implementing proper monitoring and alerting systems can help detect unusual connection patterns that may indicate an ongoing attack, allowing for more rapid response and mitigation of such denial of service incidents.