Which versions of zystcdemo are malicious?

The following npm versions of zystcdemo are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate zystcdemo if I installed it?

Remove zystcdemo 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 zystcdemo — how do I know if it already compromised me?

If zystcdemo 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.

How do I find zystcdemo across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for zystcdemo (version 1.0.0).

Malicious package

zystcdemonpm

Advisory published Oct 29, 2026Updated Nov 2, 2026

zystcdemo is a confirmed malicious npm package (MAL-2026-18447) 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 zystcdemo (npm)

MAL-2026-18447

Immediate action

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

npm uninstall zystcdemo

What this malware does

zystcdemo presents itself as a simple date formatting utility and runs its postinstall payload on npm install with node postinstall.js. The payload collects the whoami result, hostname, platform, and current time, then sends them in a POST request to https://srctest.zystcc.cn/collect; npm account zyst published it on 2026-10-29 (UTC).

Malicious versions

1 flagged

1.0.0

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for zystcdemo (version 1.0.0).
If you installed it — respond
Remove zystcdemo 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 zystcdemo 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. zystcdemo 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.

References

npmjs.com

Credits

InvisiRisk, Inc. · finder

Detect & block this

O3 blocks zystcdemo-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