zystcdemo

GHSA-xpgj-8rc5-pq44

Malicious code in zystcdemo (npm)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

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).

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/d14f5c184e0fa7acf2343c56b9bb72068b95e1bc/osv/malicious/npm/zystcdemo/MAL-2026-18447.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/d14f5c184e0fa7acf2343c56b9bb72068b95e1bc/osv/malicious/npm/zystcdemo/MAL-2026-18447.json
- https://www.npmjs.com/package/zystcdemo
- https://github.com/advisories/GHSA-xpgj-8rc5-pq44

Compromised versions (1)

= 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.