LWA-2026-5200 confirmed malware

string-utils-kit@1.0.0

Malicious code in string-utils-kit (npm)

T1195.002 · Compromise Software Supply ChainT1059.007 · JavaScriptT1204.002 · Malicious FileT1564.003 · Hidden WindowT1543 · Create or Modify System Process

Analysis

Package string-utils-kit@1.0.0 masquerades as a string utility library but executes a hidden binary on install. The postinstall hook (bin/setup.js) spawns assets/setup-helper.exe (a 9.84MB Windows PE executable) with detached:true, windowsHide:true, and child.unref() — launching it silently in the background without the installer's knowledge. The library code in dist/index.js is a decoy; the real payload is the bundled executable.

analyzed by
Leitwacht
first seen
Jun 14, 2026, 08:32 AM
analyzed
Jun 14, 2026, 08:33 AM

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Independently detected by the Leitwacht supply-chain probe. IOCs are defanged. Published CC0. Think this is a mistake? See the dispute policy.