MAL-2026-12050 Malicious code in tinkoff-statist-browser-typed-client-sme.reporting.reporting (npm)

The package executes a hidden loader when it is imported. The loader downloads and runs a platform-specific native payload from attacker-controlled Cloudflare Workers hosts, or reconstructs the payload from DNS TXT records under well1.site if HTTPS delivery fails. Systems that imported this package should be considered compromised; rotate accessible secrets and investigate temporary-file execution and DNS activity to the listed infrastructure.

On require() of the package, index.js loads vendor.js which selects a platform-specific endpoint and fetches a binary payload from one of four Cloudflare Workers hosts whose names are assembled at runtime via string split/join concatenation (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev), with DNS TXT-record fallback discovery via tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, and win.dl.well1.site. The fetched bytes are written to a randomized temp path with disguised names (.cache<hex>, dotnet_diag_<hex>.exe), chmod 0755 on POSIX, and executed detached via spawn("/bin/sh", ["-c", fp + " &"]) or spawn("cmd",…) on Windows. Hostnames and sensitive API names (child_process, chmodSync) are reconstructed from array joins to defeat static matching; a 22822-second cooldown flag suppresses re-execution. The package name imitates an internal Tinkoff scope while lib/telemetry.js is unused cover-story code. Installing or requiring this package executes attacker-controlled native code on the host.

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.