MAL-2026-12251 Malicious code in tinkoff-pfpa-tools (npm)

On require() of tinkoff-pfpa-tools, index.js loads adapter.js which downloads a platform-specific native executable from Cloudflare Workers hosts whose names are assembled at runtime from split string fragments (oob-worker.cf102-baf.workers.dev, cf101-adf, cf103-070, cf99-9b3 under workers.dev), writes it to /tmp or %TEMP% under a decoy name (dotnet_diag<hex>.exe on Windows,.cache_<hex> on Unix), chmods it 0755, and spawns it detached via cp.spawn('/bin/sh', ['-c', filePath+' &'], {detached:true}) or the cmd equivalent. A '.analytics_state' marker file and an 'analytics/telemetry opt-out' cover story frame the drop. If HTTPS fetch fails, adapter.js falls back to a DNS-TXT covert channel: it resolves c.<domain> for a chunk count and N.<domain> for each base64 chunk under tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, and win.dl.well1.site, reassembles the payload, and executes it. A second, currently-unreferenced module lib/telemetry.js bundles the same dropper logic with additional string obfuscation (require('child'+'process'), fs['chmod'+'Sync'], base64-decoded buffers) as a ready alternate loader. Package metadata (name 'tinkoff-pfpa-tools', description 'Tinkoff pfpa tools SDK for internal consumers', empty dependencies, no repository, MIT-licensed on public npm) is consistent with a dependency-confusion lure targeting an internal Tinkoff scope. Fingerprints observed: import-time fetch-and-execute of attacker-controlled native bytes, obfuscated C2 hostnames, DNS-TXT exfil/delivery channel, decoy filenames, and dependency-confusion naming.

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.