Which versions of bazelisk are malicious?

The following npm versions of bazelisk are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate bazelisk if I installed it?

bazelisk 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.

I already installed bazelisk — how do I know if it already compromised me?

If bazelisk 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.

Is bazelisk part of a known attack campaign?

Yes — bazelisk is associated with the IN-MAL-2026-018327 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find bazelisk across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bazelisk (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bazelisk across your stack and pipelines.

Malicious package

bazelisknpm

bazelisk is a confirmed malicious npm package (MAL-2026-14227) 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 bazelisk (npm)

MAL-2026-14227

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall bazelisk

What this malware does

This npm package uses the name bazelisk, colliding with Google's bazelbuild/bazelisk project (referenced in the tarball's source.txt), and self-labels as a 'Security research canary'. Its postinstall script collects the installer's hostname, platform, arch, Node version, package name, and npm lifecycle event and POSTs that JSON payload to https://grqx3qve.instances.poc.jchunt.top/bazelisk at npm install time. The destination host is unrelated to the real bazelisk publisher. Installer host identifiers and environment fingerprint leave the machine automatically on install, matching a dependency-confusion beacon pattern.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

d4bcbd35130e716d1a2940c91b6691d41b9655fdc8587404af37bc6e5a7f1370

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bazelisk (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bazelisk across your stack and pipelines.
If you installed it — respond
bazelisk 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 bazelisk 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 bazelisk 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

No. bazelisk 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-2026-018327

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bazelisk-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

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