CVE-2006-1102 in Sauerbraten
Summary
by MITRE
Sauerbraten 2006_02_28, as derived from the Cube engine, allows remote attackers to cause a denial of service (client exit) by forcing the server to change to a map (ogz) file whose name contains ".." sequences and has a certain length that prevents the addition of the ".ogz" extension.
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Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2006-1102 affects Sauerbraten version 2006_02_28, which is built upon the Cube engine architecture. This security flaw represents a classic buffer overflow condition that manifests through improper input validation in the map file handling mechanism. The vulnerability specifically targets the server's map loading process where it fails to properly sanitize file names containing directory traversal sequences. When an attacker crafts a malicious map filename containing ".." sequences that exceed a predetermined length threshold, the server's file processing logic becomes corrupted, leading to an abrupt client termination.
The technical implementation of this vulnerability stems from inadequate path validation within the engine's file system operations. The Cube engine, upon receiving a map file request, performs a series of string operations to construct the final file path by appending the ".ogz" extension to the provided filename. However, the validation routine does not properly handle cases where directory traversal sequences appear in the filename, particularly when these sequences are combined with specific length constraints that cause the path construction to fail catastrophically. This condition creates a scenario where the server's internal state becomes corrupted, resulting in an unhandled exception that terminates the client connection.
From an operational perspective, this vulnerability enables remote attackers to perform denial of service attacks against Sauerbraten servers without requiring any authentication or privileged access. The impact extends beyond simple service disruption as it can be exploited repeatedly to maintain persistent availability issues for legitimate users. The vulnerability is particularly concerning because it can be triggered through normal game operations such as map changes or server configuration updates, making it difficult to distinguish between legitimate and malicious requests. The attack vector requires minimal technical expertise and can be automated, making it a significant threat to server availability and user experience.
The underlying cause of this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-22, which covers improper limitation of a pathname to a restricted directory. The attack pattern follows the typical TTPs associated with denial of service attacks in networked applications, where an attacker manipulates input data to cause unintended program behavior. The vulnerability demonstrates a fundamental flaw in the engine's input sanitization process and highlights the importance of proper path validation in game server environments. The specific length constraint in the exploit suggests that the vulnerability exists in the string manipulation functions that handle file path construction, where the combination of directory traversal sequences and length limits causes the internal buffer management to fail.
Mitigation strategies should focus on implementing comprehensive input validation for all file operations within the server environment. The most effective approach involves sanitizing all map filenames to prevent the inclusion of directory traversal sequences and enforcing strict length limitations on file names. Additionally, the server should implement proper exception handling to prevent client termination when malformed paths are encountered. System administrators should consider implementing network-level filtering to detect and block suspicious file name patterns. The vulnerability also underscores the importance of keeping game engines updated with security patches, as similar issues have been addressed in later versions of the Cube engine and its derivatives. Organizations should also implement monitoring solutions to detect unusual patterns of map loading requests that could indicate exploitation attempts.