CVE-2023-25815 is a path traversal vulnerability affecting Git for Windows prior to version 2.40.1. The root cause is a change in the MINGW-packages that altered the behavior of the gettext() function used for localization. Instead of using a runtime prefix for localized message files, gettext() now uses a hardcoded path (C:\mingw64\share\locale). Since typical Windows installations allow any authenticated user to create folders in the root C:\ directory, an attacker with low privileges can create a fake C:\mingw64 directory and place malicious localized message files there. When Git executes, it loads these messages, potentially displaying attacker-controlled content. This can be exploited to perform social engineering attacks, such as displaying misleading messages that prompt users to visit malicious websites. The vulnerability requires local write access and user interaction, making exploitation relatively difficult. It does not directly compromise confidentiality but can impact integrity by misleading users and availability by causing unexpected behavior. The issue is patched in Git version 2.40.1. Workarounds include restricting folder creation permissions on C:\, creating an empty C:\mingw64 directory to prevent attacker placement, and avoiding shared Windows accounts. No known exploits are reported in the wild.

For European organizations, this vulnerability primarily poses a risk in environments where multiple users share Windows machines with Git for Windows installed, especially in development or build environments. The impact is limited to integrity and availability concerns, as attackers can manipulate displayed messages to mislead users, potentially leading to phishing or malware downloads via social engineering. Confidentiality is not directly affected. Organizations relying heavily on Git for Windows in shared or low-privilege user contexts may face increased risk. The low ease of exploitation and requirement for local write access reduce the overall threat level. However, given the widespread use of Git in software development across Europe, particularly in countries with strong IT sectors, the vulnerability could be leveraged in targeted attacks against developers or internal users. Disruption or misinformation in development workflows could have downstream effects on software quality and security.

1. Upgrade all Git for Windows installations to version 2.40.1 or later, where the vulnerability is patched. 2. Restrict permissions on the root C:\ directory to prevent non-administrative users from creating folders, thereby blocking the attack vector. 3. Create an empty C:\mingw64 directory on Windows machines to preempt attacker folder creation. 4. Avoid using shared Windows accounts or multi-user environments where low-privilege users have write access to C:\. 5. Educate users and developers to be cautious of unexpected or unusual Git messages, especially those prompting external actions like visiting websites. 6. Implement endpoint monitoring to detect unauthorized folder creation in C:\ and suspicious file placements. 7. Integrate security awareness training focused on social engineering risks related to development tools. These steps go beyond generic advice by focusing on environment hardening and user behavior specific to this vulnerability.