CVE-2025-7619: Arbitrary File Write Vulnerability in BatchSignCS

Overview

In the realm of cybersecurity, there’s a newly discovered vulnerability that’s raising concerns among Windows users. The vulnerability, officially named CVE-2025-7619, affects BatchSignCS, a background application developed by WellChoose that’s used in various capacities on Windows platforms globally. This vulnerability matters because it can lead to a potential system compromise or data leakage, creating a serious risk for businesses and individuals alike. It’s especially worrisome because if a user visits a malicious website while the BatchSignCS application is running, remote attackers can exploit this vulnerability to write arbitrary files to any path and potentially execute arbitrary code.

Vulnerability Summary

CVE ID: CVE-2025-7619
Severity: High (8.8 CVSS score)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

BatchSignCS | All current versions

How the Exploit Works

The vulnerability lies in the BatchSignCS’s improper validation of user-supplied data. If a user visits a malicious website and a particular set of conditions are met, the BatchSignCS application can be tricked into writing files to arbitrary paths on the user’s system. This means that an attacker could create, modify, or delete any file on the system, potentially leading to arbitrary code execution if the file is associated with an executable program.

Conceptual Example Code

Here’s a conceptual example of how this vulnerability might be exploited. The attacker sends a malicious payload to the vulnerable endpoint, which is then processed by the BatchSignCS application.

GET /malicious_website HTTP/1.1
Host: attacker.com
Content-Type: application/json
{ "file_path": "C:\\Windows\\System32\\malicious_file.exe", "file_content": "BASE64_ENCODED_MALICIOUS_CODE" }

In this example, the attacker is attempting to write malicious code to the Windows System32 directory, which houses many of the operating system’s critical files. If successful, this could lead to the execution of arbitrary code with the permissions of the BatchSignCS application.

Mitigation Steps

Users are strongly urged to apply the vendor patch as soon as it is available. As an interim measure, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can help to mitigate the vulnerability. They can potentially block or alert on attempts to exploit this vulnerability, reducing the risk of a successful attack. Cybersecurity best practices such as keeping software up to date, avoiding untrusted websites, and regularly backing up data should also be followed.