CVE-2017-6903 in ioquake3
Summary
by MITRE
In ioquake3 before 2017-03-14, the auto-downloading feature has insufficient content restrictions. This also affects Quake III Arena, OpenArena, OpenJK, iortcw, and other id Tech 3 (aka Quake 3 engine) forks. A malicious auto-downloaded file can trigger loading of crafted auto-downloaded files as native code DLLs. A malicious auto-downloaded file can contain configuration defaults that override the user's. Executable bytecode in a malicious auto-downloaded file can set configuration variables to values that will result in unwanted native code DLLs being loaded, resulting in sandbox escape.
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Analysis
by VulDB Data Team • 08/25/2024
The vulnerability identified as CVE-2017-6903 represents a critical security flaw in the ioquake3 engine and its various derivatives including Quake III Arena, OpenArena, OpenJK, and iortcw. This issue stems from insufficient content restrictions within the auto-downloading feature that governs how game clients automatically retrieve and process files from remote servers. The vulnerability operates at the intersection of software security and sandboxing principles, where the engine's trust model is fundamentally compromised by its handling of automatically retrieved content.
The technical flaw manifests through a sophisticated sandbox escape mechanism that leverages the engine's auto-download functionality to execute malicious code. When a client downloads files automatically from a remote server, the system fails to properly validate or restrict the content types that can be processed. This weakness allows attackers to craft malicious files that contain configuration defaults designed to override user settings. The vulnerability specifically targets the engine's handling of executable bytecode within auto-downloaded files, which can manipulate configuration variables to force the loading of native code DLLs. This process effectively bypasses the intended security boundaries of the game engine's execution environment.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise through sandbox escape techniques. Attackers can exploit this flaw to load arbitrary native code DLLs that are not part of the legitimate game installation, effectively allowing for arbitrary code execution within the context of the running game process. The implications are particularly severe given that these engines are widely distributed and used across multiple platforms, meaning the attack surface is extensive. The vulnerability can be exploited through network-based attacks without requiring local system access, making it particularly dangerous for online gaming environments.
This vulnerability aligns with CWE-434, which addresses the insecure download of executable code, and demonstrates characteristics consistent with ATT&CK technique T1106 for execution through DLL loading. The flaw represents a classic example of privilege escalation through improper input validation and insufficient content restrictions. The affected systems are particularly vulnerable because the auto-download feature is typically enabled by default in many game configurations, making exploitation relatively straightforward for attackers who can control remote servers or intercept network traffic. Mitigation strategies should focus on implementing strict content validation for auto-downloaded files, disabling auto-download functionality when not required, and ensuring that all downloaded content undergoes proper security scanning before execution. The vulnerability also highlights the importance of proper sandboxing mechanisms and the need for robust input validation in game engines that handle network-based content processing.