The FBI's Denver Field Office has issued a national warning over a rising cyber threat involving fake file converter websites. These sites, posing as free tools for tasks like converting documents or media formats, are secretly distributing ransomware and malware while appearing to perform legitimate functions.

According to the FBI, users are lured by services that convert files such as '.doc' to '.pdf' or combine image files, but the downloaded output often contains hidden malware.

A recent case revealed that a site impersonating Convertio delivered RedLine Stealer, a dangerous strain that harvests sensitive data from browsers, crypto wallets, and applications like Telegram and Discord.

Security experts have identified multiple malicious domains involved, with active incidents reported in the US, Denver area, just weeks ago.

The FBI urges the public to avoid unknown converter sites, keep antivirus software updated, and use built-in conversion features within trusted apps.