MAL-2026-10187

Supply-chain compromise of the official jscrambler npm client, a legitimate JavaScript obfuscation tool with roughly 60K downloads per month. Version 8.14.0 was published from the legitimate publisher account (jscrambler_ / info@jscrambler.com), which points to an account or CI compromise rather than a typosquat. Compared to the clean 8.13.0, version 8.14.0 adds a new preinstall hook (node dist/setup.js) and a new 7.5MB dist/intro.js file (entropy 8.00) that is a custom-packed, multi-platform binary container (magic bytes 1b435349 01); both are absent in 8.13.0. At install time, setup.js gunzips the platform-matched payload from intro.js, writes it to a randomly named file under the OS temp directory with the executable bit set (0o755, or a .exe extension on Windows built via String.fromCharCode), then spawns it detached with unref and windowsHide while swallowing all errors. The result is a silent, install-time native-binary dropper. Multiple releases are compromised (8.14.0, 8.16.0, 8.17.0, 8.18.0, 8.20.0); the mechanism above was analyzed on 8.14.0. Version 8.13.0 is clean.

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Source: amazon-inspector (afb577cf150e98ebfe551df006c555204f327432baa3789473981888761a8677)

The package's main entry (dist/index.js) contains a top-level IIFE that runs on every require('jscrambler'). It reads a bundled 7.8 MB sibling file dist/intro.js, validates a custom container header (0x1b 0x43 0x53 0x49 0x01), selects a platform-specific gzip section (linux/win32/darwin), writes the decompressed bytes to os.tmpdir() under a hidden random dot-file name with mode 0755, and spawns the binary detached with stdio ignored and windowsHide, then unrefs the child. Errors are swallowed. The bundled payload dist/intro.js is not JavaScript: it uses a custom multi-platform container and contains strings characteristic of a cryptocurrency-wallet seed-phrase harvester and a browser-session stealer, including the BIP-39 English wordlist...