CVE-2007-4642 in Doomsday
Summary
by MITRE
Multiple buffer overflows in Doomsday (aka deng) 1.9.0-beta5.1 and earlier allow remote attackers to execute arbitrary code via a long chat (PKT_CHAT) message that is not properly handled by the (1) D_NetPlayerEvent function in d_net.c or the (2) Msg_Write function in net_msg.c, or (3) many commands that are not properly handled by the NetSv_ReadCommands function in d_netsv.c; or (4) cause a denial of service (daemon crash) via a chat (PKT_CHAT) message without a final \0 character.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability described in CVE-2007-4642 represents a critical security flaw in the Doomsday engine version 1.9.0-beta5.1 and earlier, which is a modernization of the classic Doom engine designed for networked multiplayer gaming. This vulnerability manifests through multiple buffer overflow conditions that occur during the processing of network communications, specifically when handling chat messages and command sequences within the game's networking infrastructure. The affected components include core networking functions responsible for player event handling, message writing, and command reading operations, making this a comprehensive attack surface that could potentially compromise entire game servers and client systems.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the Doomsday engine's networking stack. The buffer overflows occur when the D_NetPlayerEvent function in d_net.c fails to properly validate the length of incoming PKT_CHAT messages, allowing attackers to craft maliciously long chat messages that exceed allocated buffer boundaries. Similarly, the Msg_Write function in net_msg.c and the NetSv_ReadCommands function in d_netsv.c exhibit identical vulnerabilities where network command processing does not enforce proper bounds checking, leading to memory corruption that can be exploited to execute arbitrary code. These flaws directly map to CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflows, both of which are fundamental weaknesses in memory management that enable code execution attacks.
The operational impact of this vulnerability extends beyond simple code execution to encompass potential denial of service scenarios that could render game servers completely inoperable. When attackers send chat messages lacking the required null termination character, the system experiences daemon crashes due to improper handling of malformed input data, effectively causing a denial of service condition that prevents legitimate players from accessing the game service. This dual nature of the vulnerability makes it particularly dangerous for multiplayer gaming environments where server stability and availability are paramount. The attack vectors align with ATT&CK technique T1203, which describes exploitation of software vulnerabilities for code execution, while also demonstrating characteristics of T1499, which involves the disruption of services through system resource exhaustion or crash conditions.
Mitigation strategies for this vulnerability require immediate patching of the Doomsday engine to version 1.9.0-beta5.2 or later, which contains the necessary fixes for buffer overflow conditions in the affected networking functions. System administrators should implement network monitoring to detect unusual chat message patterns and malformed network packets that could indicate exploitation attempts. Additionally, the implementation of proper input validation and bounds checking mechanisms within the application code should be enforced through secure coding practices that prevent similar vulnerabilities from occurring in future versions. Network segmentation and access controls should be deployed to limit exposure of vulnerable game servers, while regular security audits should verify that all networking components properly handle edge cases and malformed input data. The vulnerability serves as a reminder of the critical importance of proper memory management in networked applications and demonstrates how seemingly minor input handling flaws can result in significant security implications across multiple attack vectors.