@s4yhiitestpoc/r2-https

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: amazon-inspector (b6042f718b39be380eeda7c31dc46b056e753cb8a39e51897c8106e49b44f4d0)
On npm install, the package's declared postinstall script (postinstall.js) collects installer host fingerprint data — hostname, username, home directory, platform/arch/OS release, current working directory, install directory, DNS server list, non-internal network interface addresses, Node.js version, and npm_* environment values including npm_config_registry — and POSTs the collected JSON to https://collector.oob.s4yhii.com/_npm-poc/beacon. It additionally performs an out-of-band DNS lookup against a subdomain of oob.s4yhii.com (db03o8lag74hsugsg2j091t8mfcf437h3.oob.s4yhii.com) to confirm execution via DNS exfiltration. The destination is a hardcoded author-controlled domain, the behavior fires automatically at install time without consent, and the exfiltrated data includes npm_config_registry which can disclose an internal/private registry URL. A self-described 'PoC' or 'coordinated disclosure' framing does not change the fact that installer-identifying data and internal registry configuration leave the host to a third-party endpoint.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/ff41f6680a0ebbef2268cdb5daf253d4b400cb05/osv/malicious/npm/@s4yhiitestpoc/r2-https/MAL-2026-17764.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/ff41f6680a0ebbef2268cdb5daf253d4b400cb05/osv/malicious/npm/@s4yhiitestpoc/r2-https/MAL-2026-17764.json
- https://www.npmjs.com/package/@s4yhiitestpoc/r2-https/v/1.0.0
- https://github.com/advisories/GHSA-r3vq-5g6w-hwmm

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.