LWA-2026-10030 MAL-2026-11712 ↗ confirmed malware

@or-sdk/markdowner@0.5.3

Malicious code in @or-sdk/markdowner (npm)

T1059.007 · JavaScriptT1027 · Obfuscated Files or InformationT1105 · Ingress Tool Transfer

Analysis

The package's preinstall hook (setup.mjs) downloads the Bun JavaScript runtime from the oven-sh/bun GitHub releases and uses it to execute a 727KB obfuscated script (math_init.js) bundled in the package. The script is obfuscated with a large encoded string array and a custom decoder, and contains eval/Function/child_process usage. The package also declares a dependency on @or-sdk/base. The obfuscated payload's network behavior is not visible statically.

analyzed by
Leitwacht
first seen
Aug 4, 2026, 11:59 AM
analyzed
Aug 4, 2026, 04:01 PM
weekly installs
120

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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.