unico-checknpm
unico-check is a confirmed malicious npm package (MAL-2026-5830) that opens a backdoor for remote access (malicious version 9.9.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in unico-check (npm)
What this malware does
package.json declares a preinstall lifecycle hook that runs curl against https://webhook.site/fe1246c2-ac04-4493-b223-fe34ba26b79f, passing the installer's hostname, current user, working directory, full uname -a output, and $HOME as query parameters. The beacon fires automatically on npm install with no user interaction. The package ships no source files, declares no main entry, and uses the implausible version 9.9.9 — the canonical shape of a dependency-confusion / typosquat reconnaissance package targeting builds that may resolve a private unico-check from the public registry. The package's only effect on installation is to leak host identifiers to an anonymous, attacker-controlled webhook.site bin, staging follow-on compromise.
The OpenSSF Package Analysis project identified 'unico-check' @ 9.9.9 (npm) as malicious.
It is considered malicious because:
- The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for unico-check (version 9.9.9). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging unico-check across your stack and pipelines.
If you installed it — respond
unico-check 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.
Did it already run?
If unico-check was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks unico-check before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks unico-check-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.