MAL-2026-12262 Malicious code in tinkoff-statist-browser-typed-client-investing.product.pulse (npm)

The package's main entrypoint (index.js) unconditionally requires bootstrap.js, which downloads a platform-specific executable from a rotating list of Cloudflare Workers subdomains (oob-worker.cf10{0,1,3}-*.workers.dev) with a DNS TXT fallback resolved via *.dl.well1.site, writes it to a disguised path (.cache<rnd>, dotnet_diag_<rnd>.exe), chmods it to 755, and spawns it detached via /bin/sh or cmd. Destination hostnames are reconstructed at runtime from split string arrays (e.g. ['oob-worker.','cf10','2-baf.','workers','.dev'].join('')) and API names are assembled dynamically (fs['chmod'+'Sync']) to evade static inspection. No hash or signature verification of the fetched binary is performed, and the fetched host is unrelated to any publisher domain. A second parallel dropper is bundled in lib/telemetry.js (base64 payload assembly + cp.spawn('/bin/sh', ['-c', filePath+' &']) + fs['chmod'+'Sync'] to 0755) shipped in the tarball. The package name impersonates a Tinkoff internal scope with no plausible legitimate purpose matching the observed behavior.

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.