MalwarePublished 14 Jul 2026

assertion-utils-js (npm) · Malicious Code

Affects assertion-utils-jsSource GCVE Database

Malicious package : remove assertion-utils-js and rotate any secrets on hosts that installed it.

Data as of 15 Jul 2026, 12:55 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-10612

What to do

Remove assertion-utils-js from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmassertion-utils-js	Affected =2.4.3	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

The npm package assertion-utils-js is a malicious typosquat of the legitimate chai package. When required, it spawns a detached Node.js child process that runs heavily obfuscated code which fetches and executes remote code with full Node module privileges. This behavior effectively compromises any system running the package. The package version 2.4.3 is affected. Removal of the package does not guarantee full remediation as the system may already be fully compromised.

Impact

Any computer with assertion-utils-js version 2.4.3 installed or running is considered fully compromised. The attacker gains full control via remote code execution with Node.js privileges. All secrets and keys stored on the compromised system should be considered exposed and must be rotated from a secure environment. Removing the package alone may not remove all malicious artifacts or backdoors installed by the attacker.

Defensive guidance

Remove the assertion-utils-js package version 2.4.3 immediately. Rotate all secrets and keys that were stored or used on the compromised system from a different, secure computer. Because the system may be fully compromised, consider rebuilding or thoroughly cleaning the affected environment.

Summary

assertion-utils-js is a typosquatting malicious package mimicking chai. Upon loading, it spawns a detached Node.js child process executing obfuscated code that reconstructs a URL, fetches remote JavaScript code via HTTPS, and executes it dynamically with full Node.js privileges. This allows arbitrary remote code execution on any system that loads the package. The obfuscation is designed to evade static analysis by hiding the fetch destination. The malicious behavior occurs on every load of the package, leading to a full system compromise risk.

References

Community reviews

Loading reviews…

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2026, 12:55 UTC

Technical details

References

Community reviews