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Malicious package

@s4yhiitestpoc/scan-https-dnpm

Advisory published Updated

@s4yhiitestpoc/scan-https-d is a confirmed malicious npm package (MAL-2026-17766) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @s4yhiitestpoc/scan-https-d (npm)

MAL-2026-17766
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall @s4yhiitestpoc/scan-https-d

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. 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 collects installer host identity — os.hostname(), os.userInfo().username, home directory, cwd, non-internal network interface addresses, DNS servers, and platform/arch/release — and POSTs it as JSON over HTTPS to the hardcoded endpoint https://collector.oob.s4yhii.com/_npm-poc/beacon, with a secondary DNS lookup against *.oob.s4yhii.com as an out-of-band execution signal. The package's scope (@s4yhiitestpoc/*) and metadata self-describe this as a dependency-confusion proof-of-concept targeting internal namespaces that resolve to the public registry; the self-labeling does not change the fact that installer host identifiers leave the installer's machine on install to a hardcoded third-party domain the installer did not opt into.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

1a1dd63de3f5e380c573cd6bcf885c9d0c7a5c503959dfde1a6c8b963a6ddaea

Detection & response playbook

Backdoor / remote access

  1. Find it

    Search your lockfiles and build artifacts for @s4yhiitestpoc/scan-https-d (version 1.0.0).

  2. If you installed it — respond

    @s4yhiitestpoc/scan-https-d establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

  3. Did it already run?

    If @s4yhiitestpoc/scan-https-d 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. @s4yhiitestpoc/scan-https-d 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.

Campaign

IN-MAL-2026-021434

References

Credits

  • Amazon Inspector · finder
  • SecOpsAI Research · finder

Detect & block this

O3 blocks @s4yhiitestpoc/scan-https-d-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
@s4yhiitestpoc/scan-https-d (npm) malicious package — MAL-2026-17766 | O3 Security