tinkoff-ui-actionnpm
tinkoff-ui-action is a confirmed malicious npm package (MAL-2026-12051) that executes malicious code on install (malicious version 20.5.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tinkoff-ui-action (npm)
What this malware does
On require of the package's main entry, compat.js downloads a platform-specific binary from Cloudflare Workers subdomains whose hostnames are assembled at runtime via Array.join to evade static analysis (e.g. oob-worker.cf*.workers.dev), with a DNS-TXT chunked-base64 fallback across tin.dl.well1.site, tina.dl.well1.site, ldr.dl.well1.site, and win.dl.well1.site. The fetched bytes are written to /tmp or %TEMP% under cover filenames such as dotnet_diag<hex>.exe and.cache_<hex>, chmodded 0755 on POSIX, and detached-spawned via /bin/sh -c '<path> &' or cmd.exe /c start /b <path>. lib/telemetry.js contains the same download-write-chmod-spawn pattern with obfuscated require("child_"+"process") and fs["chmod"+"Sync"] under an 'Analytics SDK' cover, providing a secondary payload runner. There is no hash or signature verification, no user consent, and the package is advertised as a React UI component library — a purpose unrelated to fetching and executing native binaries. Runtime string-splitting of both hostnames and dangerous API names is deliberate anti-analysis.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tinkoff-ui-action (version 20.5.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tinkoff-ui-action across your stack and pipelines.
If you installed it — respond
Remove tinkoff-ui-action from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If tinkoff-ui-action 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-ui-action 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-ui-action-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.