A new What’s a malware strain disguised as software cracks and commercial tools uses a just-in-time generation tactic to create unique variants for each download request. This method allows the malware to evade detection by security systems that rely on pre-compiled hashes. The malware delays its malicious actions until specific buttons are clicked during the installation process, at which point it downloads and executes additional payloads from a Command and Control (C2) server.
Researchers have observed this malware installing various harmful programs, including information stealers, proxy tools, clickers disguised as browser plugins, and even legitimate software such as the Opera browser and 360 security products. The malware can tailor the C2 server address and itself for each download request, making detection difficult. In environments where it has been downloaded before, the attacker may deliver a benign WinRAR file instead.
The malware is created using InnoSetup and requires users to click “Next” twice during installation to trigger malicious behavior. It uses InnoDownloadPlugin to download additional installers from a C2 server, which then executes malicious actions upon receiving an “ok” response. To evade analysis, the C2 server might switch its response to “no,” causing the installation to terminate without executing any malicious activities.
The InnoLoader malware functions as a multi-stage downloader, fetching and executing various malicious payloads such as StealC Infostealer, which can steal user credentials, browser information, and potentially cryptocurrency wallet/FTP logins. It communicates with multiple C2 servers, downloading additional payloads like the Socks5Systemz proxy and adware disguised as a Windows update tool. This complex downloader-dropper-payload chain makes the malware challenging to analyze and prevent, as it generates unique instances and employs multiple tools to steal user data and establish persistence.
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