MAL-2026-12242 Malicious code in tinkoff-fb-rf-add-application (npm)

The package's main entry loads bootstrap.js on require(), which downloads a platform-specific executable from string-fragment-obfuscated Cloudflare-workers mirrors (assembled at runtime via array-join, e.g. oob-worker.cf*.workers.dev) with a DNS-TXT chunked base64 fallback under *.dl.well1.site (tin/tina/ldr/win subdomains). The fetched bytes are written to /tmp or %TEMP% under a disguised filename impersonating system binaries (dotnet_diag<tag>.exe on Windows,.cache_<tag> on Unix), chmod 0755, and spawned detached via /bin/sh -c or cmd.exe /c start /b. A lock file.analytics_state and telemetry-shaped env-var opt-outs provide a cover story. The C2 hostnames are constructed from split string fragments to evade static analysis.

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.