Description

A recent variant of the ClearFake malware framework has emerged, using fake reCAPTCHA and Cloudflare Turnstile verifications to trick users into executing malicious PowerShell code. Initially discovered in July 2023, ClearFake has evolved significantly, moving from simple JavaScript injections to more sophisticated tactics. This new strain is leveraging Web3 functionality, more specifically the Binance Smart Chain, to provide malware through defaced websites. The malware exchanges data with blockchain smart contracts so that it is able to load payloads dynamically without having to reconfigure the exploited sites themselves. ClearFake's malicious approach starts with a short JavaScript injection, often into WordPress websites, that loads more malicious code from the Binance Smart Chain. The script employs the web3 library to download encrypted payloads, which are contained in smart contracts. The payloads are gzip-compressed and base64-encoded, so they must be decoded and decompressed before running. This approach makes it difficult for malware to be detected using conventional methods and to be flexible in its attacks. The malware is programmed to install loaders like the Emmenhtal Loader, which downloads information-stealing malware like Lumma Stealer and Vidar Stealer. The loaders are specifically designed to steal confidential data from compromised systems. One of the most important features of the new variant is that it employs fake reCAPTCHA and Cloudflare Turnstile checks, with an additional social engineering component that makes it more difficult for users to distinguish between authentic security features and threats. This is an important measure that increases the sophistication of the attack substantially, making detection by both users and security mechanisms much more challenging. ClearFake's changing strategies highlight the expanding potential of Web3-based malware and the necessity for increased cybersecurity protocols. The deployment of dynamic payload delivery through smart contracts is a major change to the method by which malware can spread, necessitating new approaches to protection against this more advanced method of cyberattack.