Which versions of modsync are malicious?

The following npm versions of modsync are flagged malicious: 5.0.2. Treat any of these as compromised.

How do I remediate modsync if I installed it?

Remove modsync from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

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

If modsync 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 modsync part of a known attack campaign?

Yes — modsync is associated with the IN-MAL-2026-018373 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 modsync across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for modsync (version 5.0.2).

Malicious package

modsyncnpm

Advisory published Aug 19, 2026Updated Aug 19, 2026

modsync is a confirmed malicious npm package (MAL-2026-14257) that executes malicious code on install (malicious version 5.0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in modsync (npm)

MAL-2026-14257

Immediate action

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

npm uninstall modsync

What this malware does

The package presents itself as a pino-like logger/middleware (README, docs/, and index.d.ts copied from pinojs/pino; keywords fast/logger/stream/json) but its exported middleware is a no-op. index.js unconditionally requires ./lib/config, which is a 4 MB single-line file bearing obfuscator.io fingerprints (hex-named identifiers, a ~23,909-entry rotating string array, decoder functions, control-flow flattening, hex string escapes) and executes a top-level IIFE at module load. Consumers that require('modsync') execute this obfuscated blob in their process. Package metadata is inconsistent with the advertised purpose (name modsync combined with pino keywords, description referencing vulnerability management, author Robert King <[email protected]>, bugs URL jsonspack.com/issues). The combination of a plagiarized cover-story shell around a large obfuscated require-time payload is characteristic of a malicious package rather than legitimate business logic; the obfuscation exists to hide behavior from inspection.

Malicious versions

1 flagged

5.0.2

Indicators of compromise (SHA-256)

04b786780800de5689c4ae50377166b26050fd688ec5d75cfb14fda990b92494

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for modsync (version 5.0.2).
If you installed it — respond
Remove modsync from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If modsync 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. modsync on npm has been identified as a malicious package (version 5.0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-018373

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks modsync-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

Explore

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