CVE-2006-1593 in X-Doom
Summary
by MITRE
The (1) ZD_MissingPlayer, (2) ZD_UseItem, and (3) ZD_LoadNewClientLevel functions in sv_main.cpp for (a) Zdaemon 1.08.01 and (b) X-Doom allows remote attackers to cause a denial of service (crash) via an invalid player slot or item number, which causes an invalid memory access, possibly due to an invalid array index.
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Analysis
by VulDB Data Team • 05/04/2025
The vulnerability identified as CVE-2006-1593 represents a critical denial of service flaw affecting the Zdaemon game server software version 1.08.01 and its derivative X-Doom. This issue manifests within three specific functions within the sv_main.cpp source file namely ZD_MissingPlayer, ZD_UseItem, and ZD_LoadNewClientLevel. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize player slot identifiers and item number parameters submitted by remote clients. When malformed or out-of-bounds values are processed through these functions, they result in invalid memory access conditions that ultimately lead to server crashes and complete service disruption.
The technical implementation of this vulnerability falls under the category of improper input validation and memory safety issues, which aligns with CWE-125, improper input validation, and CWE-787, out-of-bounds write operations. The flaw operates by accepting user-supplied data without adequate bounds checking, allowing attackers to submit invalid array indices that reference memory locations outside the allocated buffer space. This creates a scenario where the server process attempts to access memory regions that are either unmapped or protected, triggering segmentation faults and subsequent application termination. The vulnerability is particularly dangerous in multiplayer gaming environments where server stability directly impacts the gaming experience for all connected players.
From an operational perspective, this vulnerability presents a significant risk to game server administrators and network operators who rely on stable server performance for their gaming communities. The remote exploit capability means that any individual with network access to the affected server can trigger the denial of service condition without requiring local system access or authentication credentials. The impact extends beyond simple server crashes to potentially disrupting ongoing gameplay sessions, causing player data loss, and creating service availability issues that can damage the reputation of gaming platforms and communities. The vulnerability demonstrates the critical importance of input validation in networked applications, particularly those handling real-time multiplayer interactions where server stability is paramount.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation mechanisms within the affected functions. The most effective approach involves adding proper bounds checking for all player slot and item number parameters before any memory access operations occur. This includes validating that provided indices fall within acceptable ranges and implementing proper error handling for invalid inputs rather than allowing them to propagate to memory access operations. Additionally, developers should implement robust logging mechanisms to detect and alert on suspicious input patterns that may indicate attempted exploitation. The fix should be implemented following secure coding practices that align with the principles outlined in the OWASP Secure Coding Practices and the CERT Secure Coding Standards. Server administrators should also consider implementing network-level protections such as rate limiting and input filtering to reduce the effectiveness of potential exploitation attempts. Regular security updates and patch management procedures should be established to ensure that similar vulnerabilities are identified and addressed promptly across all networked applications.