MAL-2026-12148 Malicious code in bigops-api-mobile (npm)

On require() of the package, index.js loads runtime.js which selects a platform-specific endpoint from a list of Cloudflare Workers subdomains reconstructed at runtime via array-join string splits (oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev), downloads bytes over HTTPS with no hash or signature verification, writes them to a disguised temp file (.cache<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmods 0755, and spawns the file detached via cp.spawn("/bin/sh",["-c", fp+" &"]) or cmd. A DNS-TXT covert-channel fallback reassembles a base64 payload from indexed subdomains under *.wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru) when HTTPS fails. lib/telemetry.js ships a second copy of the dropper primitives (Buffer.from(chunks,"base64"); fs["chmod"+"Sync"] via dynamic property access; cp.spawn("/bin/sh",["-c", filePath+" &"])), providing a staged secondary activation path. Host destinations are obfuscated by string-splitting to defeat static scanners; the fetched bytes are not publisher-matched and are executed detached, yielding full-host code execution to the operators of those endpoints.

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.