CVE-2010-0406 in OpenTTD
Summary
by MITRE
OpenTTD before 1.0.1 allows remote attackers to cause a denial of service (file-descriptor exhaustion and daemon crash) by performing incomplete downloads of the map.
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Analysis
by VulDB Data Team • 09/08/2021
The vulnerability identified as CVE-2010-0406 affects OpenTTD versions prior to 1.0.1, presenting a significant denial of service risk that can be exploited remotely by attackers. This flaw specifically targets the application's handling of map file downloads, where incomplete download operations can be manipulated to exhaust system resources. The vulnerability operates through a sophisticated mechanism that leverages the application's file descriptor management system, creating a scenario where multiple incomplete download attempts can accumulate and eventually deplete available file descriptors on the system. This resource exhaustion ultimately leads to the daemon crashing and becoming unresponsive to legitimate user requests, effectively rendering the service unavailable.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within OpenTTD's download handling subsystem. When users attempt to download maps from remote servers, the application maintains file descriptors for each download operation, even when those operations are interrupted or incomplete. The flaw occurs because the application fails to properly clean up these file descriptors when downloads are terminated prematurely or fail to complete successfully. This represents a classic resource leak pattern that aligns with CWE-404, which catalogs improper resource release or cleanup issues. The vulnerability specifically exploits the application's failure to implement proper cleanup routines for incomplete download sessions, creating a persistent state where file descriptors remain open indefinitely.
The operational impact of CVE-2010-0406 extends beyond simple service disruption to potentially compromise system stability and availability for legitimate users. Attackers can exploit this vulnerability by initiating multiple simultaneous incomplete map downloads, causing the system to exhaust its file descriptor limit and forcing the OpenTTD daemon to crash. This type of attack can be particularly damaging in multi-user environments where the service supports numerous concurrent connections, as it can effectively shut down access to the game service for all users. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks targeting application availability. The attack vector requires no special privileges or authentication, making it particularly dangerous as it can be executed by anyone with access to the network service.
Mitigation strategies for this vulnerability require both immediate patching and architectural improvements to prevent similar issues in the future. The most effective immediate solution involves upgrading to OpenTTD version 1.0.1 or later, where the developers have implemented proper cleanup mechanisms for incomplete download sessions and improved file descriptor management. System administrators should also consider implementing connection limits and download timeout mechanisms to prevent exploitation through resource exhaustion attacks. Additionally, monitoring for unusual patterns of incomplete download attempts can help detect potential exploitation attempts. The vulnerability demonstrates the importance of implementing robust resource management practices and proper error handling in networked applications, particularly those that handle file transfers and user connections. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of such attacks, while maintaining regular vulnerability assessments to identify similar resource management flaws in other systems.