CVE-2007-4631 in QGit
Summary
by MITRE
The DataLoader::doStart function in dataloader.cpp in QGit 1.5.6 and other versions up to 2pre1 allows local users to overwrite arbitrary files and execute arbitrary code via a symlink attack on temporary files with predictable filenames.
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Analysis
by VulDB Data Team • 07/27/2019
The vulnerability identified as CVE-2007-4631 represents a critical security flaw in QGit version 1.5.6 and earlier releases, specifically within the DataLoader::doStart function located in dataloader.cpp. This issue constitutes a classic symlink attack vulnerability that exploits predictable temporary file naming conventions to enable unauthorized file overwrites and arbitrary code execution. The flaw arises from insufficient validation of temporary file creation processes, allowing local attackers to manipulate the system's temporary file handling mechanisms through symbolic link manipulation.
The technical implementation of this vulnerability stems from the predictable naming patterns used for temporary files within the QGit application's data loading functionality. When the DataLoader::doStart function processes data, it creates temporary files with known, predictable filenames that can be easily targeted by malicious users. Attackers can create symbolic links with these predictable names in the temporary directory before the legitimate application attempts to create the same files. This race condition scenario enables the attacker to control what gets written to the temporary files, potentially allowing them to inject malicious content that will be executed when the application processes these files.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass full arbitrary code execution capabilities. Local attackers can leverage this weakness to escalate their privileges within the system, potentially gaining elevated access rights that would otherwise be restricted. The vulnerability affects any user running affected versions of QGit, making it particularly dangerous in multi-user environments where attackers might exploit this weakness to gain unauthorized access to system resources. This type of vulnerability directly aligns with CWE-367, which describes the "Time-of-Check to Time-of-Use" (TOCTOU) race condition, and also maps to ATT&CK technique T1059 for execution through command and script interpreters.
Mitigation strategies for CVE-2007-4631 should focus on implementing proper temporary file handling mechanisms that eliminate predictable naming patterns and prevent symbolic link manipulation. System administrators should immediately upgrade to patched versions of QGit where available, as the vulnerability has been addressed in subsequent releases through improved temporary file creation procedures. Additional protective measures include implementing proper file permissions on temporary directories, using secure temporary file creation functions that prevent symlink attacks, and ensuring that applications validate the integrity of temporary files before processing them. Organizations should also conduct thorough security audits to identify other applications that might be susceptible to similar TOCTOU race conditions, particularly those that handle user-supplied data or create temporary files during processing operations.