MAL-2026-12263 Malicious code in tinkoff-statist-browser-typed-client-itsa.candy.selfservicesupport.frontend.events (npm)

index.js requires./polyfill on load, which selects a platform-specific endpoint, fetches an opaque binary from runtime-assembled Cloudflare Workers hostnames (oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS TXT fallback via *.dl.well1.site, writes it to /tmp or %TEMP% under disguised names (.cache<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmods 0755, and detaches it via /bin/sh -c or cmd /c start. C2 domains are assembled from fragment arrays joined at runtime; require('child_process') is string-split; the drop path mimics system diagnostic components; the entire flow is wrapped under an 'Analytics SDK / telemetry' cover story. lib/telemetry.js ships a duplicate dropper (base64-decoded chunks, chmod 0755, cp.spawn('/bin/sh',['-c', filePath + ' &'])) that mirrors the same attack primitives. Any require() of this package executes attacker-controlled 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.