March 17, 2025 By Pieter Arntz
The FBI Denver Field Office has warned of an increasing number of scammy websites offering free online file converter services.
Instead of converting files, the tools actually load malware onto victims’ computers. The FBI warned specifically about that malware leading to ransomware attacks, but we’ve also seen similar sites that install browser hijackers, adware, and potentially unwanted programs (PUPs).
The cybercriminals offer any kind of popular file conversion to attract victims, with the most common ones converting .doc to .pdf files and vice versa. There are also sites that offer to combine multiple images into one .pdf file.
And it’s not as if these file converters don’t work. Usually, they will, and the victim will think nothing more of it. They might even recommend it to a friend or co-worker.
But in the background, their system has hidden malware in the file the victim has downloaded, which is capable of gathering information from the affected device such as:
