Which versions of assertcore are malicious?

The following npm versions of assertcore are flagged malicious: 3.1.7. Treat any of these as compromised.

How do I remediate assertcore if I installed it?

assertcore is a typosquat — you almost certainly intended a legitimately-named package. Remove assertcore, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed assertcore — how do I know if it already compromised me?

If assertcore was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is assertcore part of a known attack campaign?

Yes — assertcore is associated with the IN-MAL-2026-007415 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 assertcore across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for assertcore (version 3.1.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging assertcore across your stack and pipelines.

Malicious package

assertcorenpm

Malicious code in assertcore (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-6365

Immediate action

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

npm uninstall assertcore

What this malware does

Package assertcore impersonates the popular chai assertion library (ships a copy of chai source as cover; author and homepage differ from the genuine project). On require('assertcore') / import 'assertcore', index.js spawns a detached node subprocess running lib/chai/utils/addAssertion.js with stdio set to ignore: const chaiBinding = spawn("node", [addAssertion, JSON.stringify(args)], {detached: true, stdio: "ignore"}). The spawned script is heavily obfuscated using obfuscator.io string-array rotation, a base64-with-substitution decoder, and hex-arithmetic indexing to hide that it requires http(s), performs a GET to a URL assembled from obfuscated literals, and passes the response body into new Function('require', body)(require) — executing attacker-supplied JavaScript with full Node privileges on every install or require. The combination of name impersonation, chai-source cover, detached/silenced subprocess, obfuscated network destination, and import-time fetch-and-eval is an unambiguous supply-chain attack on installers.

Malicious versions

1 flagged

3.1.7

Indicators of compromise (SHA-256)

4bd2844909a6dd6db77af2d47b2d9a16ff126d892998282f4df4c7ed1f61a4af

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for assertcore (version 3.1.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging assertcore across your stack and pipelines.
If you installed it — respond
assertcore is a typosquat — you almost certainly intended a legitimately-named package. Remove assertcore, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If assertcore was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks assertcore before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. assertcore on npm has been identified as a malicious package (version 3.1.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007415

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks assertcore-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