MAL-2026-13828 Malicious code in ms_aidc_com_tw (npm)

The package ms_aidc_com_tw ships only an index.html that renders a fake Cloudflare Turnstile 'security verification' page. On Turnstile completion, heavily obfuscated JavaScript (obfuscator.io-style rotating string array _0x59f1, RC4/base64 decoder _0x2020, self-defending anti-debug checks) assembles a URL to login.microsoftonline.com, copies the current page's query-string parameters onto it, and calls window.location.replace to hand the victim off to Microsoft's real login with attacker-controlled parameters preserved — the standard adversary-in-the-middle / OAuth-consent phishing relay pattern. The package name impersonates a Microsoft-branded Taiwanese corporate domain (ms.aidc.com.tw). The obfuscation exists solely to conceal the phishing destination and the parameter-relay logic from casual review. The npm registry is being abused as hosting infrastructure for a Microsoft 365 credential-harvesting landing page.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.