Malicious actors are increasingly exploiting web browsers to deliver malware, often bypassing conventional antivirus defenses through sophisticated social engineering. A notable tactic involves copying harmful commands into the clipboard, allowing victims to execute them unknowingly. Recent investigations revealed a campaign using malicious advertisements and counterfeit pages that mimic reputable software brands, leading victims to a fake Cloudflare notification that prompts them to execute specific key combinations. This process triggers PowerShell code that retrieves and installs malware.
The investigation began with a suspicious advertisement for a 'notepad' application, which redirected users to a Cloudflare-like page asking them to verify they are human. Instead of a standard CAPTCHA, users encountered a prompt instructing them to follow steps that would inadvertently execute a malicious command. By clicking a 'Fix It' button, the harmful command is copied to the clipboard, and users are led to paste and run it, initiating a download from a remote domain.
The campaign targeted several brands, including Microsoft Teams, FileZilla, UltraViewer, CutePDF, and Advanced IP Scanner. The same domain linked to the malicious PowerShell command for Notepad++ also appeared in another campaign. Indicators of compromise include various malicious domains and URLs associated with the malware and its command and control server. Malwarebytes provides protection against these threats.