@s4yhiitestpoc/r3-httpsnpm
Advisory published Updated
@s4yhiitestpoc/r3-https is a confirmed malicious npm package (MAL-2026-17765) that steals credentials and exfiltrates sensitive data (malicious versions 0.0.0-stage, 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @s4yhiitestpoc/r3-https (npm)
What this malware does
Dependency-confusion proof-of-concept package. A postinstall script runs automatically on installation and sends host and user identifiers (hostname, username, home directory, network interface addresses, platform details and npm configuration) to collector.oob.s4yhii.com, with a secondary DNS lookup under oob.s4yhii.com. It also performs a reverse DNS lookup of the host's own address and records the name and path of the project that installed it. The script states it is bug-bounty research and does not read secrets or file contents. Any machine that installed this package disclosed the listed host information to a third party.
On npm install, postinstall.js automatically collects host identity (hostname, username, uid/gid, homedir, platform, release), enumerates network interfaces (addresses, MACs, CIDRs), reads DNS servers and internal reverse-DNS names, captures npm/CI environment markers and container/runtime indicators, and walks up to eight parent directories to locate the consuming project's package.json and extract its name, version, declaring dependency field, and declared version range. The collected data is POSTed over HTTPS to the hardcoded endpoint collector.oob.s4yhii.com at path /_npm-poc/beacon, and a parallel DNS lookup to a labeled subdomain under *.oob.s4yhii.com is issued as an out-of-band beacon. The consumer manifest harvesting discloses the installer's private project identity and internal package naming to a third-party host and is the characteristic reconnaissance signal of a dependency-confusion targeting pipeline. The endpoint is not caller-configurable and there is no opt-out.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for @s4yhiitestpoc/r3-https (2 malicious versions).
If you installed it — respond
@s4yhiitestpoc/r3-https is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If @s4yhiitestpoc/r3-https 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
Campaign
References
Credits
- Amazon Inspector · finder
- SecOpsAI Research · finder
Detect & block this
O3 blocks @s4yhiitestpoc/r3-https-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.