agency-test-exercise (npm) · Malicious Code
Affects agency-test-exerciseSource GCVE Database
Malicious package : remove agency-test-exercise and rotate any secrets on hosts that installed it.
Data as of 25 Sep 2026, 04:49 UTC
Malicious package
Published to npm · OSV MAL-2026-17170
What to do
Remove agency-test-exercise from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| npmagency-test-exercise | Affected
| Fixed in– |
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Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (43eddaf152e2aa60b9f823513a2d9b11fc424a5cff4bb3c031f6823a48dc2f4e) package.json declares a postinstall hook `wscript.exe 4444.vbs` that fires automatically on `npm install`. The shipped 4444.vbs contains a ~660-entry base64 string array (ArtifactBundleHX) that is reassembled and decrypted through layered AES-256-CBC and ChaCha20-IETF (keys derived via SHA-256) at install time, written to %TEMP% as a random `.dat` file, and passed to powershell.exe as a two-tier loader for in-memory execution / process hollowing. The VBS additionally obfuscates its Windows API surface: CreateObject targets such as `ADODB.Stream` and `Msxml2.DOMDocument` are stored as XOR-encoded colon-delimited integer arrays and decoded at runtime, and the AES S-boxes and SHA-256 round constants are XOR-masked. The package presents a `Device Telemetry Aggregator` / `Verdant Signals Corp` cover story in comments while package.json ships empty author and description fields. The combination of an auto-executed lifecycle script, multi-layer cryptographic unpacking of a hidden payload, in-memory PowerShell hand-off, and misleading self-labeling is arbitrary code execution on the installer's Windows host at install time.