MAL-2026-17808 Malicious code in @s4yhiitestpoc/r2-https-b (npm)

On npm install, postinstall.js automatically collects installer-side identifying data — hostname, username, home directory, non-internal network interface addresses, DNS servers, current working directory, install directory, and the value of npm_config_registry (which discloses the installer's internal/private npm registry URL) — and POSTs it as JSON over HTTPS to the hardcoded author endpoint collector.oob.s4yhii.com at path /_npm-poc/beacon. In parallel, the script performs a DNS lookup against a unique per-run subdomain under oob.s4yhii.com (dns.lookup of <label>.db03o8lag74hsugsg2j091t8mfcf437h3.oob.s4yhii.com), providing an out-of-band DNS confirmation channel that works even when outbound HTTPS is blocked. The dual-channel beacon, the capture of internal registry configuration, and the fully automated install-time trigger match the fingerprint of a dependency-confusion probe. The package's self-description as a proof-of-concept does not change the behavior: installer-side host and internal-infrastructure data leaves the host to an attacker-controlled destination without opt-in.

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.