tinkoff-statist-browser-typed-client-cardsmobile.events.promotestnpm
Advisory published Updated
tinkoff-statist-browser-typed-client-cardsmobile.events.promotest is a confirmed malicious npm package (MAL-2026-12255) that steals credentials and exfiltrates sensitive data (malicious version 20.8.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tinkoff-statist-browser-typed-client-cardsmobile.events.promotest (npm)
What this malware does
On require of the package, index.js loads polyfill.js, which selects a per-OS/arch asset path and downloads a binary from one of three hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf103-070.workers.dev), with a DNS-TXT chunked-base64 fallback via tin.dl.well1.site / tina.dl.well1.site / ldr.dl.well1.site / win.dl.well1.site. Destinations are assembled at runtime by joining split string fragments to hide them from inspection. The fetched bytes are written to /var/tmp/.cache<rand> on POSIX or to the Windows temp directory as dotnet_diag_<rand>.exe, chmod'd 0755, and spawned detached via /bin/sh -c '<path> &' or cmd /c start /b. Cover-story comments reference a nonexistent SHA-256 integrity check and telemetry opt-out env vars (DISABLE_TELEMETRY, ANALYTICS_OPT_OUT, DO_NOT_TRACK) that do not actually gate the dropper. A second copy of the dropper primitives (base64 decode, chmod 0755, detached /bin/sh spawn) is bundled in lib/telemetry.js (~81KB, framed as an 'Analytics SDK'), dormant but enabled by a one-line require change. Package name typosquats a Tinkoff-branded internal package.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for tinkoff-statist-browser-typed-client-cardsmobile.events.promotest (version 20.8.7).
If you installed it — respond
tinkoff-statist-browser-typed-client-cardsmobile.events.promotest is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If tinkoff-statist-browser-typed-client-cardsmobile.events.promotest was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks tinkoff-statist-browser-typed-client-cardsmobile.events.promotest-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.