Which versions of c2-client are malicious?

The following npm versions of c2-client are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate c2-client if I installed it?

c2-client 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 c2-client — how do I know if it already compromised me?

If c2-client 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.

Is c2-client part of a known attack campaign?

Yes — c2-client is associated with the IN-MAL-2026-020513 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 c2-client across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for c2-client (version 1.0.0).

Malicious package

c2-clientnpm

Advisory published Sep 24, 2026Updated Sep 24, 2026

c2-client is a confirmed malicious npm package (MAL-2026-17165) 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 c2-client (npm)

MAL-2026-17165

Immediate action

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

npm uninstall c2-client

What this malware does

The package name is 'c2-client' and package.json declares a postinstall hook that executes 'node setup.js' automatically on npm install. The setup script runs unattended in the installer's environment with the installer's privileges and network access. Combined with the package's self-declared C2-client purpose, install of this package is expected to establish an attacker-controlled command channel or execute attacker-controlled code on the installer's machine at install time.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

8c5e21fe48a0a1a03a1846e11cb06360950603c3bd8ccba5979c431c84779ba0

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for c2-client (version 1.0.0).
If you installed it — respond
c2-client 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 c2-client 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. c2-client 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-2026-020513

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks c2-client-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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