LWA-2026-8028 MAL-2026-11598 ↗ confirmed malware

@onereach/expression-components@9.1.3

Malicious code in @onereach/expression-components (npm)

T1059.007 · JavaScriptT1105 · Ingress Tool Transfer

Analysis

The package's preinstall hook (setup.mjs) downloads the Bun JavaScript runtime from github[.]com/oven-sh/bun/releases and executes a bundled 727KB script (math_init.js) with it during installation. math_init.js is heavily obfuscated with a custom string-table encoding, making its runtime behavior opaque; it is executed automatically on install with no opt-in. No plaintext C2/exfil endpoint was observed in the readable portion of the package.

analyzed by
Leitwacht
first seen
Aug 4, 2026, 01:16 PM
analyzed
Aug 4, 2026, 03:34 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.