LWA-2026-7907 MAL-2026-11637 ↗ confirmed malware

@onereach/si-dropdown-advanced@0.4.7

Malicious code in @onereach/si-dropdown-advanced (npm)

T1059.007 · JavaScriptT1105 · Ingress Tool TransferT1027 · Obfuscated Files or Information

Analysis

The package's preinstall hook (node setup.mjs) downloads the Bun JavaScript runtime from github[.]com/oven-sh/bun and executes a 727KB obfuscated payload (math_init.js) at install time. The payload is obfuscated with a custom base64-style decoder and large string-array constants, hiding its behaviour. A UI dropdown component has no legitimate need to download a runtime and run an obfuscated payload during npm install; this is a trojanized package executing attacker-controlled code on the installer's machine.

analyzed by
Leitwacht
first seen
Aug 4, 2026, 12:38 PM
analyzed
Aug 4, 2026, 01:41 PM

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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.