Which versions of nested-lib are malicious?

The following npm versions of nested-lib are flagged malicious: 1.0.0, 1.0.1, 1.1.0. Treat any of these as compromised.

How do I remediate nested-lib if I installed it?

nested-lib 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 nested-lib — how do I know if it already compromised me?

If nested-lib 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 nested-lib part of a known attack campaign?

Yes — nested-lib is associated with the IN-MAL-2026-021399, IN-MAL-2026-021402, IN-MAL-2026-021404 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 nested-lib across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for nested-lib (3 malicious versions).

Malicious package

nested-libnpm

Advisory published Oct 11, 2026Updated Oct 11, 2026

nested-lib is a confirmed malicious npm package (MAL-2026-17773) that opens a backdoor for remote access (malicious versions 1.0.0, 1.0.1, 1.1.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in nested-lib (npm)

MAL-2026-17773

Immediate action

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

npm uninstall nested-lib

What this malware does

The package declares scripts.postinstall = "node beacon.cjs" and index.js also invokes require('./beacon.cjs').fire() at module load. beacon.cjs POSTs a JSON payload containing os.hostname(), __dirname, process.cwd(), and process.version over plain HTTP to the hardcoded bare-IP endpoint http://185.158.107.175:8787/_ah/dc. The destination is not a documented first-party service and the host identifiers are sent without any opt-in. index.js otherwise exports a Proxy that returns no-op functions for every property access, so the package provides no real functionality — its sole on-install and on-require effect is the beacon. The combination of a hollow Proxy shim, a bare-IP plain-HTTP destination, and automatic firing from both the npm lifecycle hook and the main module is consistent with a reconnaissance/confirmation beacon used to validate successful installation into target environments, typically preceding a second-stage payload.

Malicious versions

3 flagged

1.0.01.0.11.1.0

Indicators of compromise (SHA-256)

0a0b849de5330a4a4984a855f83ce1638b17e459d359312319ff35dc0e02f928

ab87d579d75ebc0c4d4bbeeb2d27aedbe7350e0522cd34b00947f7d802d9148f

b5cf1b7875d61d769d7b3d89e1695a3bd8425947919ef47cae55579700507ab9

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for nested-lib (3 malicious versions).
If you installed it — respond
nested-lib 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 nested-lib 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. nested-lib on npm has been identified as a malicious package (versions 1.0.0, 1.0.1, 1.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-021399IN-MAL-2026-021402IN-MAL-2026-021404

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks nested-lib-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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