Which versions of js-assert-plus are malicious?

The following npm versions of js-assert-plus are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate js-assert-plus if I installed it?

Remove js-assert-plus 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 js-assert-plus — how do I know if it already compromised me?

If js-assert-plus 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 js-assert-plus part of a known attack campaign?

Yes — js-assert-plus is associated with the IN-MAL-2026-017643 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 js-assert-plus across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for js-assert-plus (version 1.0.0).

Malicious package

js-assert-plusnpm

Advisory published Aug 13, 2026Updated Aug 13, 2026

js-assert-plus is a confirmed malicious npm package (MAL-2026-13953) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in js-assert-plus (npm)

MAL-2026-13953

Immediate action

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

npm uninstall js-assert-plus

What this malware does

The npm package js-assert-plus masquerades as an assertion library (homepage http://js-assert-plus.com) and bundles the real chai source so consumers get working functionality while a loader runs on every require/import. index.js hex-decodes the strings 'child_process' and 'spawn' and spawns a detached node subprocess running lib/chai/utils/assertion.js. That sibling module is packed with obfuscator.io string-array obfuscation (rotated array _0x1b90, base64+decodeURIComponent decoder) that reconstructs a URL at runtime, performs an https GET, and passes the response body to new Function('require', body)(require) — executing attacker-controlled JavaScript on the installer's machine with require in scope. Both the require of child_process and the network destination are hidden behind runtime string reconstruction so static inspection cannot see the endpoint.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

acbf16a8956847ff7ed56158afe65bc0bf76cb36f8cb6af6bc143cae4cb9babe

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for js-assert-plus (version 1.0.0).
If you installed it — respond
Remove js-assert-plus 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 js-assert-plus 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. js-assert-plus on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-017643

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks js-assert-plus-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

All malware advisories How O3 detects malware Vulnerability database