Critical Malicious Code Vulnerability in test-agency-assignment Package
Summary
MAL-2026-17239: Malicious code in test-agency-assignment (npm). Affects test-agency-assignment versions 1.0.2. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
The test-agency-assignment package is an npm module designed for managing agency assignments in JavaScript applications. It is commonly used in various projects for its ease of integration and functionality. However, this package has been found to contain a severe vulnerability that allows for arbitrary code execution on Windows systems during installation, posing significant security risks to users.
Vulnerability Detail
The vulnerability originates from a postinstall lifecycle script defined in the package.json file, which executes a malicious VBS script (4444.vbs) upon installation. This script employs a multi-layer decoder to extract and execute a PowerShell loader, leading to arbitrary code execution on the installer's host. The malicious behavior is disguised under the guise of a 'Device Telemetry Aggregator', making it difficult for users to detect the threat. This vulnerability can lead to unauthorized access and control over the affected systems.
How To Fix
This package is malicious. Remove it and rotate any credentials it could have accessed.
npm uninstall test-agency-assignmentIf it arrived as a transitive dependency, remove the package that pulled it in, then reinstall.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
As a temporary workaround, users can avoid installing the test-agency-assignment package until a fixed version is released. Additionally, users can manually inspect the package.json file for any suspicious scripts before installation.
Conclusion
The test-agency-assignment package contains a critical vulnerability that allows for malicious code execution on Windows systems. Users are advised to update their packages and utilize tools like Vulert to monitor for vulnerabilities. Staying informed and proactive is essential for maintaining software security.
See every vulnerability recorded for test-agency-assignment →
FAQ
The vulnerability involves malicious code execution through a postinstall script that runs a harmful VBS file on Windows systems.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Visit Vulert Scanner to check your application without needing to sign up.
If you have installed the vulnerable package, you should remove it immediately and update to a patched version as soon as it becomes available.
Regularly audit your dependencies, use tools like Vulert for monitoring, and keep your packages updated to the latest versions to minimize risks.
The consequences include unauthorized access to your system, data breaches, and potential control over your machine by attackers.
