assertcoreutils (npm) · Malicious Code
Affects assertcoreutilsSource GCVE Database
Malicious package : remove assertcoreutils and rotate any secrets on hosts that installed it.
Data as of 15 Jul 2026, 12:36 UTC
Malicious package
Published to npm · OSV MAL-2026-10491
What to do
Remove assertcoreutils 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 |
|---|---|---|
| npmassertcoreutils | Affected
| Fixed in– |
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Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (1e53b085bfe045b4aeabe9ad77e1066ab0883f27304197377681191c3118b780) assertcoreutils impersonates the popular `chai` assertion library: the README, the `chai` keyword, the `lib/chai/` directory layout, and `lib/chai.js` are copied verbatim from chai. When a consumer runs `require('assertcoreutils')`, index.js calls `child_process.spawn('node', ['lib/chai/utils/addAssertion.js',...], { detached: true, stdio: 'ignore' })` followed by `.unref()`, launching a hidden, detached child that survives the parent and produces no console output. `lib/chai/utils/addAssertion.js` is encoded with obfuscator.io string-array / RC4-base64 obfuscation (hex-named identifiers `_0x2ff01b`, `_0x516b`, etc.) that hides a hardcoded HTTPS URL plus query-key; the child performs an HTTPS GET to that URL and passes the response body into `new Function('require', body)(require)`, giving the remote operator arbitrary Node-level code execution on every installer. The combination of typosquat lure, copied legitimate package contents as cover, obfuscated remote URL, detached silent child, and runtime `new Function` over fetched bytes is a supply-chain dropper. ## Source: ghsa-malware (0a5a896a613d498f5908e70719f1b9046f145713db6f66e2c5f4ef101ff46a2b) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.