MalwarePublished 9 Jul 2026

validator-string (npm) · Malicious Code

Affects validator-stringSource GCVE Database

Malicious package : remove validator-string and rotate any secrets on hosts that installed it.

Data as of 11 Jul 2026, 09:43 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-10109

What to do

Remove validator-string from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmvalidator-string	Affected =13.15.36	Fixed in–

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Description

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (41a95b09ecd097cf7db1496950d26195169adb7ad2d8065a3458771389094be4) Package name `validator-string` impersonates the widely-used npm package `validator` and copies its README, homepage, and API surface. `package.json` declares `scripts.postinstall: node index.js`, and `main` resolves to the same `index.js`, so the trailing obfuscated block runs both on `npm install` and on every `require('validator-string')`. The appended code uses a custom multi-stage character-shuffle routine to reconstruct the identifiers `require`, `module`, `__dirname`, `__filename`, `undefined`, and `constructor`, then hoists `require`/`module`/`__dirname`/`__filename` onto `global` so the decoded body has full Node.js capability. It recovers the string `Function` from `constructor`, invokes `Function(argNames, decodedBody)` on a large opaque encoded blob, and calls the resulting function unconditionally (`Lpe(2163)`). This is dynamic code construction from an obfuscated payload executed automatically on install and on load — installer-side remote/opaque code execution with full Node privileges. The typosquat name, cloned metadata, obfuscation of core Node identifiers, and auto-execution at two separate lifecycle points are collectively unambiguous.

Impact

This malicious package allows arbitrary code execution with full Node.js privileges on any system that installs or requires it. This can lead to complete compromise of the host environment, including data theft, system manipulation, or further malware deployment. The threat is severe given the automatic execution on install and load, and the full Node.js capability granted to the payload.

Defensive guidance

The best mitigation is to avoid installing or using the validator-string package. Users should verify package names carefully to avoid typosquatting attacks and rely only on the official validator package from trusted sources. Monitoring package dependencies and using tools that detect typosquatting or malicious packages can help prevent accidental installation.

Summary

The validator-string package is a malicious npm package that mimics the legitimate validator package by copying its README, homepage, and API surface. Its package.json defines a postinstall script that runs node index.js, and the main entry also points to index.js, which contains an obfuscated block of code. This code reconstructs core Node.js identifiers such as require, module, __dirname, __filename, and constructor through a multi-stage character shuffle. It then exposes these identifiers globally and dynamically constructs and executes a function from an encoded payload. This results in automatic execution of potentially harmful code both during installation and runtime, effectively enabling installer-side remote code execution with full Node privileges. The combination of typosquatting, cloned metadata, obfuscation, and dual automatic execution points clearly indicates malicious intent.

References

npmjs.com/package/validator-string/v/13.15.36 (opens in a new tab)

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What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Jul 2026, 09:35 UTC

Technical details

References

Community reviews