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Malicious package

1cat-tunnel-client-zxnpm

Advisory published Updated

1cat-tunnel-client-zx is a confirmed malicious npm package (MAL-2026-4778) that steals credentials and exfiltrates sensitive data (malicious versions 1.0.2, 1.0.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in 1cat-tunnel-client-zx (npm)

MAL-2026-4778
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall 1cat-tunnel-client-zx

What this malware does

On npm install, the package's postinstall hook (node install.js) fetches a platform-specific executable from http://156.226.174.161:8888/binaries/tunnel-client-* over plaintext HTTP, writes it to the package's bin/ directory, and chmod 0755s it. The download URL is hardcoded to a bare IP address, uses cleartext HTTP (no TLS), is not pinned to a version, and the fetched bytes are never hash- or signature-verified before being made executable. The cli.js fallback performs the same unverified download on first CLI invocation if the binary is missing. Any on-path network attacker between the installer and 156.226.174.161 — or any future operator of that IP — can substitute arbitrary native code that will then run on the installer's machine. The destination is not a known runtime CDN, not the package publisher's own infrastructure, and the package's stated purpose (a tunnel client) does not justify forgoing TLS or integrity verification. Separately, the README ships plaintext admin credentials for the author's own tunnel server, which is author self-harm and not the basis for this block.

Malicious versions

2 flagged
1.0.21.0.3

Indicators of compromise (SHA-256)

616be417e8ec33626ef98fe1056bfbd52142e3c44ed4e3158ca5f58ae7cf7331
796f1b18c13a38088b4e48d75575eb92b23af5d91cdfaf6a82717f0fabbc7a79

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for 1cat-tunnel-client-zx (2 malicious versions).

  2. If you installed it — respond

    1cat-tunnel-client-zx 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.

  3. Did it already run?

    If 1cat-tunnel-client-zx 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. 1cat-tunnel-client-zx on npm has been identified as a malicious package (versions 1.0.2, 1.0.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-004846IN-MAL-2026-004863

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks 1cat-tunnel-client-zx-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
1cat-tunnel-client-zx (npm) malicious package — MAL-2026-4778 | O3 Security