MAL-2026-13941 Malicious code in @solana-js/web3 (npm)

Package name @solana-js/web3 impersonates the legitimate @solana/web3.js SDK, and package.json falsely attributes authorship to 'Solana Labs' with a solana.com homepage. The exported API is a non-functional stub (Connection.getBalance returns 0, sendTransaction returns random bytes) — no real Solana client functionality is present. On install, scripts/postinstall.js detects Windows and spawns a hidden PowerShell (-NoP -W Hidden -Exec Bypass) with a base64-encoded command. The decoded PowerShell performs an AMSI bypass via reflection over System.Management.Automation.AmsiUtils, downloads a binary payload from https://files.catbox.moe/a3loxy.bin, and executes it in-process using VirtualAlloc/CreateThread. The postinstall script further hex-escapes API names ('child_process', 'powershell', 'platform', 'win32') and fragments the PowerShell payload to hinder review. The result is arbitrary remote code execution on any Windows host that runs npm install against this package, with the shellcode fetched from an anonymous, mutable file host (files.catbox.moe) — a known-bad-infrastructure dropper pattern.