MAL-2026-12240 Malicious code in tinkoff-fb-app-frame-page-height-dippy (npm)

On require, index.js loads platform.js, which reconstructs C2 hostnames via runtime string concatenation (joining fragments such as 'oob-worker.cf101-adf.workers.de'+'v' and 'tin.dl.well1'+'.si'+'te'), selects a per-OS/architecture binary, and downloads bytes over HTTPS from one of four anonymous Cloudflare Workers subdomains (oob-worker.cf101-adf.workers.dev, cf102-, cf103-, cf104-) with a DNS TXT-record fallback via well1.site. The retrieved payload is written to /tmp as a hidden dot-file (e.g. /tmp/.cache<rand>,.analytics_state lock file) on POSIX or to %TEMP% as dotnet_diag_<rand>.exe on Windows, chmodded 0755, and spawned detached via /bin/sh -c '<path> &' or cmd /c start. A shipped lib/telemetry.js further concatenates 'child_'+'process' and 'chmod'+'Sync' to evade static analysis. The package name and description bear no relation to this behavior; the entire on-require code path is a binary dropper executing attacker-controlled native code on the installer's 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.