Which versions of book-collect are malicious?

The following npm versions of book-collect are flagged malicious: 35.8.2. Treat any of these as compromised.

How do I remediate book-collect if I installed it?

Remove book-collect 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 book-collect — how do I know if it already compromised me?

If book-collect 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 book-collect part of a known attack campaign?

Yes — book-collect is associated with the IN-MAL-2026-015357 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 book-collect across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for book-collect (version 35.8.2).

Malicious package

book-collectnpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

book-collect is a confirmed malicious npm package (MAL-2026-13027) that executes malicious code on install (malicious version 35.8.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in book-collect (npm)

MAL-2026-13027

Immediate action

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

npm uninstall book-collect

What this malware does

On require('book-collect'), index.js loads loader.js which downloads a platform-specific binary from Cloudflare Workers hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT base64 fallback to sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. Hostnames are reconstructed at runtime via split-array.join("") and function names are built by concatenation ('child'+'process', 'chmod'+'Sync') to evade static analysis. The fetched bytes are written to /var/tmp/.cache_<rand> or %TEMP%\dotnet_diag_<rand>.exe (disguised as a dotnet diagnostic tool), chmod 0755, and spawned detached via '/bin/sh -c <path> &' or 'cmd.exe /c start /b'. No hash or signature verification is performed. A second copy of the same drop-write-chmod-exec chain lives in lib/telemetry.js under an 'Analytics SDK' cover story, with an env-var opt-out (DISABLE_TELEMETRY / ANALYTICS_OPT_OUT) that does not change the default install behavior.

Malicious versions

1 flagged

35.8.2

Indicators of compromise (SHA-256)

32d9f4b229afba5188036ffc4d7a5ac27d13339cd0f82920564cebbe13d089da

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for book-collect (version 35.8.2).
If you installed it — respond
Remove book-collect 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 book-collect 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. book-collect on npm has been identified as a malicious package (version 35.8.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015357

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks book-collect-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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