CVE-2004-1805 in Unreal Engine
Summary
by MITRE
Format string vulnerability in games using the Epic Games Unreal Engine 436 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers in class names.
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Analysis
by VulDB Data Team • 01/08/2025
The vulnerability identified as CVE-2004-1805 represents a critical format string vulnerability within games built using the Epic Games Unreal Engine 436. This flaw manifests in the engine's handling of class names during runtime execution, creating a vector through which remote attackers can manipulate memory operations. The vulnerability specifically affects applications that utilize the Unreal Engine 436 framework, which was widely adopted for developing multiplayer and single-player gaming experiences across various platforms.
The technical implementation of this vulnerability stems from improper input validation within the engine's class name processing routines. When the Unreal Engine encounters class names containing format string specifiers such as %s, %d, or %x, it fails to properly sanitize these inputs before using them in printf or similar formatting functions. This omission allows attackers to inject malicious format specifiers that can manipulate the stack, leading to unpredictable behavior. The flaw operates at the application level within the engine's runtime environment, making it particularly dangerous as it can be exploited through network-based interactions during game initialization or class loading phases.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution. When exploited successfully, attackers can cause game clients to crash or, more critically, execute arbitrary code on victim machines. This capability arises from the ability to manipulate stack pointers and overwrite memory locations through carefully crafted format string attacks. The vulnerability affects not only the targeted game applications but also the broader ecosystem of Unreal Engine 436-based software, as the flaw exists within the core engine components rather than individual game implementations. Network-based exploitation is particularly concerning as it allows attackers to target players without requiring local system access or physical presence.
From a cybersecurity perspective, this vulnerability aligns with CWE-134, which specifically addresses format string vulnerabilities in software applications. The attack pattern follows typical exploitation techniques described in the MITRE ATT&CK framework under the T1059.007 sub-technique for command and scripting interpreter. The vulnerability's classification as a remote code execution risk places it within the high-severity category of cybersecurity threats, particularly affecting gaming environments where users may be less security-conscious. Remediation efforts should focus on implementing proper input sanitization, using safe string formatting functions like snprintf instead of sprintf, and applying immediate patches from Epic Games. Organizations should also consider network segmentation and monitoring for anomalous class name patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in game engines and the need for comprehensive security testing of core framework components to prevent widespread exploitation across multiple applications.