Malicious code in stestenv (npm)

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (ee35b23a60484ee1d468154734cc7cdbc8c7d3cbc81901ab680cb67e46a8c2b6) On require of the package's main entry, `dispatchAnalytics()` reads a payload hidden in the JPEG APP13 (marker 0xFFED) segment of the bundled `dist/stest.jpg`, decrypts it with a hardcoded AES-256-CBC key to obtain a UTF-16LE PowerShell command, writes a VBScript to the OS tmpdir, and launches it via `wscript.exe` to run `powershell.exe -NoProfile -NonInteractive -EncodedCommand <payload>`. Runtime binary names are string-split (`"power"+"shell"`, `"wscript"+".exe"`) and the process is spawned detached with `windowsHide:true` and `.unref()` to evade lexical scanners and hide the window. A companion `dist/decode.js` confirms the encrypted PowerShell payload format (hardcoded 32-byte key, AES-256-CBC, UTF-16LE, re-base64 for `-EncodedCommand`). The bundled cli embeds an inlined `package.json` with a different identity (`name:"node-env-buffer", version:"2.2.6"`) than the published `stestenv` name, indicating the same dropper is being redistributed under multiple names while presenting a dotenv-style cover story. Installing or importing this package on Windows results in silent execution of attacker-controlled code hidden inside a shipped image asset.

Source published

30 Sep 2026 01:27:20 UTC

Source modified

30 Sep 2026 01:45:11 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.