tinkoff-fb-fieldset-car-reference-kaskonpm
tinkoff-fb-fieldset-car-reference-kasko is a confirmed malicious npm package (MAL-2026-12241) that typosquats a legitimate package to trick installs (malicious version 20.7.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tinkoff-fb-fieldset-car-reference-kasko (npm)
What this malware does
On module load, index.js requires./shim.js, which immediately runs a dropper: it fetches an opaque platform-specific binary from hardcoded Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT chunk fallback across tin/tina/ldr/win.dl.well1.site, writes it to /tmp or %TEMP% under cover names (.cache<hex> on Unix, dotnet_diag_<hex>.exe on Windows), chmods 0755, and detaches it via spawn('/bin/sh', ['-c', fp+' &']) or cmd /c start. A freshness marker at /tmp/.analytics_state gates re-runs. Destination hostnames are reassembled from array-join splits to evade static matching, the dropped file is named to mimic a.NET diagnostic tool, and a DISABLE_TELEMETRY opt-out is used as cover. No hash or signature verification is performed on the fetched bytes. Any consumer importing this package receives arbitrary attacker code execution 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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tinkoff-fb-fieldset-car-reference-kasko (version 20.7.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tinkoff-fb-fieldset-car-reference-kasko across your stack and pipelines.
If you installed it — respond
tinkoff-fb-fieldset-car-reference-kasko is a typosquat — you almost certainly intended a legitimately-named package. Remove tinkoff-fb-fieldset-car-reference-kasko, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If tinkoff-fb-fieldset-car-reference-kasko was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks tinkoff-fb-fieldset-car-reference-kasko before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks tinkoff-fb-fieldset-car-reference-kasko-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.