The tinkoff-ui-action npm package version 20.5.7 includes malicious functionality that, upon requiring its main entry, downloads platform-specific executable binaries from dynamically constructed Cloudflare Workers subdomains and fallback domains using runtime string assembly to evade static detection. These binaries are saved to temporary locations with obfuscated filenames, permissioned for execution, and launched in a detached manner. Additionally, the package contains a secondary payload runner in lib/telemetry.js that uses obfuscated Node.js APIs to perform similar download and execution steps under the guise of an 'Analytics SDK'. There is no integrity verification or user consent involved. This behavior effectively grants remote code execution capabilities and full system compromise to an attacker controlling the downloaded payloads.

Any system with tinkoff-ui-action version 20.5.7 installed or running is considered fully compromised due to the package's capability to download and execute arbitrary native code without user consent or verification. This can lead to complete loss of confidentiality, integrity, and availability of the affected system. All secrets, credentials, and keys stored on the compromised system should be assumed exposed and must be rotated immediately from a secure environment. Removal of the package alone does not guarantee eradication of all malicious artifacts or persistence mechanisms.

Remove the tinkoff-ui-action package version 20.5.7 immediately from all affected systems. Rotate all secrets, keys, and credentials that were stored or used on compromised systems from a separate, trusted device. Conduct a thorough investigation and remediation of the affected systems, as full compromise is likely. There is no known patch or fixed version available; therefore, avoid using this package until a trustworthy update is released. Monitor for any suspicious activity related to this package or its downloaded payloads.