CVE-2010-3199 in TortoiseSVN
Summary
by MITRE
Untrusted search path vulnerability in TortoiseSVN 1.6.10, Build 19898 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse dwmapi.dll that is located in the same folder as a file that is processed by Tortoise. NOTE: this is only a vulnerability when a file extension is associated with TortoiseProc or TortoiseMerge, which is not the default.
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Analysis
by VulDB Data Team • 02/07/2019
The vulnerability described in CVE-2010-3199 represents a significant security flaw in TortoiseSVN version 1.6.10 and earlier, specifically targeting the software's handling of dynamic link library (dll) loading mechanisms. This untrusted search path vulnerability stems from the application's failure to properly validate the source of dynamically loaded libraries, creating an environment where malicious actors can execute arbitrary code through carefully crafted file associations. The flaw manifests when users process files through TortoiseSVN's command processing utilities, particularly TortoiseProc and TortoiseMerge, which are designed to handle various file types within the version control system. The vulnerability's exploitation potential extends beyond local users to potentially include remote attackers, making it particularly concerning for environments where users might encounter untrusted files through network shares or other external sources.
The technical implementation of this vulnerability relies on the Windows operating system's dynamic link library loading behavior, which searches for required libraries in a specific order including the current working directory before checking system directories. When a file extension is associated with TortoiseSVN's processing utilities, the application loads the target file from a directory that may contain malicious libraries. The specific Trojan horse library mentioned in the description is dwmapi.dll, a legitimate Windows system library that when replaced with a malicious version, can execute arbitrary code with the privileges of the user running TortoiseSVN. This mechanism enables attackers to perform DLL hijacking attacks, where the malicious library is loaded instead of the legitimate one, effectively allowing code execution without user interaction. The vulnerability's impact is amplified by the fact that it requires only a specific file extension association to be present, which is not the default configuration, but can be easily modified by users or administrators.
The operational implications of CVE-2010-3199 are substantial, as it provides attackers with a pathway to execute arbitrary code on systems where TortoiseSVN is installed and configured with vulnerable file associations. The attack vector is particularly dangerous because it can be initiated through seemingly benign file processing operations, making it difficult for users to detect malicious activity. The vulnerability creates a persistent threat model where attackers can place malicious dwmapi.dll files in directories containing files that will be processed by TortoiseSVN, effectively creating a backdoor mechanism that can be activated whenever those files are accessed. This type of vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which specifically addresses the issue of applications not properly controlling the search paths used to locate dynamic libraries. The attack scenario described in the vulnerability description corresponds to ATT&CK technique T1574.001 Dynamic Link Library Hijacking, which focuses on the manipulation of dynamic link library loading mechanisms to execute malicious code.
Mitigation strategies for this vulnerability center around proper configuration management and system hardening practices. The most effective immediate solution is to ensure that file associations with TortoiseSVN utilities are not configured in a way that creates untrusted search paths, particularly avoiding associations that process files in user-accessible directories. System administrators should implement the principle of least privilege by restricting write access to directories containing TortoiseSVN utilities and associated files. Additionally, the vulnerability can be addressed through proper patch management, ensuring that all systems have been updated to TortoiseSVN versions that properly handle dynamic library loading without creating security risks. Network administrators should monitor for suspicious file operations and implement application whitelisting policies that restrict which applications can be executed in contexts where the vulnerability might be exploited. The vulnerability also highlights the importance of maintaining awareness of default configurations and ensuring that security settings are properly implemented, as the issue only becomes exploitable when non-standard file associations are configured, indicating that users may be inadvertently creating security risks through their configuration choices.