test-agency-assignment

Details

**Severity:** Critical

**Affected versions:** `= 1.0.2`

## Source: amazon-inspector (dcdf62e1c1eb44ca7a29ed37c12bdb71883025a46c5066e58c9228f0dfe782c2)
package.json declares a postinstall lifecycle script `wscript.exe 4444.vbs`, causing the VBS file shipped in the tarball to run automatically on `npm install` on Windows hosts. 4444.vbs contains a hand-rolled multi-layer decoder (Base64, an XOR-masked AES S-box, ChaCha20-IETF, additional XOR) that concatenates hundreds of embedded ~2KiB Base64 chunks stored in `ArtifactBundleHX(...)`, decrypts them, writes the resulting PowerShell loader to a randomly named file under %TEMP% (`pf<rand>.dat`), and invokes powershell.exe against it. In-file comments describe the handoff to PowerShell as being for process hollowing. The file header presents a benign 'Device Telemetry Aggregator' cover story that does not match the shipped behavior. The package's only functional content is this dropper; installing the package on Windows results in arbitrary attacker-controlled code execution on the installer's host.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/501714751ba269514a0a7215c211de39b4230b65/osv/malicious/npm/test-agency-assignment/MAL-2026-17239.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/501714751ba269514a0a7215c211de39b4230b65/osv/malicious/npm/test-agency-assignment/MAL-2026-17239.json
- https://www.npmjs.com/package/test-agency-assignment/v/1.0.2
- https://github.com/advisories/GHSA-7x83-rfhr-656r

Compromised versions (1)

• = 1.0.2

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.