Which versions of distributorblock are malicious?

The following npm versions of distributorblock are flagged malicious: 35.8.1. Treat any of these as compromised.

How do I remediate distributorblock if I installed it?

Remove distributorblock 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 distributorblock — how do I know if it already compromised me?

If distributorblock was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Is distributorblock part of a known attack campaign?

Yes — distributorblock is associated with the IN-MAL-2026-016875 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 distributorblock across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for distributorblock (version 35.8.1).

Malicious package

distributorblocknpm

Advisory published Aug 7, 2026Updated Aug 7, 2026

distributorblock is a confirmed malicious npm package (MAL-2026-13503) that executes malicious code on install (malicious version 35.8.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in distributorblock (npm)

MAL-2026-13503

Immediate action

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

npm uninstall distributorblock

What this malware does

The package's main entry (index.js) re-exports a decoy telemetry module and unconditionally require()s setup.js. On require, setup.js selects a platform-specific path, downloads an opaque binary from one of four hardcoded Cloudflare Workers hosts under oob-worker.cf*.workers.dev (assembled via string concatenation to obscure the literal), writes it to /var/tmp/.cache_<hex> on POSIX or %TEMP%\dotnet_diag_<hex>.exe on Windows, sets mode 0755, and spawns it detached via /bin/sh -c or cmd.exe with stdio ignored and unref(). A /tmp flag file rate-limits repeated runs and a DO_NOT_TRACK check gates execution. When HTTP retrieval fails, setup.js reassembles the payload from base64-encoded chunks served over DNS TXT records at c.<domain> and 0..N.<domain> under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru — a covert channel that bypasses HTTP egress controls. The package's declared purpose ("API client wrappers") is inconsistent with fetching and executing a native binary at import time, and author metadata is empty. The naming (.cache_, dotnet_diag_), detached spawn, and DNS-TXT fallback are consistent with a trojan dropper designed to evade both sandboxing and network defenses.

Malicious versions

1 flagged

35.8.1

Indicators of compromise (SHA-256)

f8b9a4f0d7d51b904c51afac9543f8acc9e91d33277512dc9294a24e966903ea

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for distributorblock (version 35.8.1).
If you installed it — respond
Remove distributorblock 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 distributorblock was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. distributorblock on npm has been identified as a malicious package (version 35.8.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-016875

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks distributorblock-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

Explore

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