Which versions of stestenv are malicious?

The following npm versions of stestenv are flagged malicious: 1.0.1. Treat any of these as compromised.

How do I remediate stestenv if I installed it?

Remove stestenv from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed stestenv — how do I know if it already compromised me?

If stestenv was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is stestenv part of a known attack campaign?

Yes — stestenv is associated with the IN-MAL-2026-020785 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find stestenv across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for stestenv (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging stestenv across your stack and pipelines.

Malicious package

stestenvnpm

stestenv is a confirmed malicious npm package (MAL-2026-17309) that executes malicious code on install (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in stestenv (npm)

MAL-2026-17309

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall stestenv

What this malware does

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.

Malicious versions

1 flagged

1.0.1

Indicators of compromise (SHA-256)

ee35b23a60484ee1d468154734cc7cdbc8c7d3cbc81901ab680cb67e46a8c2b6

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for stestenv (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging stestenv across your stack and pipelines.
If you installed it — respond
Remove stestenv from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If stestenv was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks stestenv before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. stestenv on npm has been identified as a malicious package (version 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020785

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks stestenv-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

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