tinkoff-fb-rf-add-applicationnpm
tinkoff-fb-rf-add-application is a confirmed malicious npm package (MAL-2026-12242) that opens a backdoor for remote access (malicious version 20.3.5). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tinkoff-fb-rf-add-application (npm)
What this malware does
The package's main entry loads bootstrap.js on require(), which downloads a platform-specific executable from string-fragment-obfuscated Cloudflare-workers mirrors (assembled at runtime via array-join, e.g. oob-worker.cf*.workers.dev) with a DNS-TXT chunked base64 fallback under *.dl.well1.site (tin/tina/ldr/win subdomains). The fetched bytes are written to /tmp or %TEMP% under a disguised filename impersonating system binaries (dotnet_diag<tag>.exe on Windows,.cache_<tag> on Unix), chmod 0755, and spawned detached via /bin/sh -c or cmd.exe /c start /b. A lock file.analytics_state and telemetry-shaped env-var opt-outs provide a cover story. The C2 hostnames are constructed from split string fragments to evade static analysis.
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
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tinkoff-fb-rf-add-application (version 20.3.5). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tinkoff-fb-rf-add-application across your stack and pipelines.
If you installed it — respond
tinkoff-fb-rf-add-application establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If tinkoff-fb-rf-add-application 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-rf-add-application 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-rf-add-application-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.