Cybersecurity company Malwarebytes is urging internet users to exercise caution when seeking free online file conversion tools, warning that some of these services are embedding malware into their downloads. The cybersecurity firm’s latest research, published in March 2025, reveals how attackers disguise malicious software as legitimate file converters to infect unsuspecting victims’ devices.
According to Malwarebytes’ blog post, titled “Warning over free online file converters that actually install malware,” these sites lure users with promises of quick and easy file format conversions. However, when users upload documents for conversion, they are often prompted to install “helper” applications that actually deliver harmful payloads. These malicious programs can track browsing activity, steal passwords, or open backdoors that grant remote access to cybercriminals.
“Users should always be skeptical of websites that insist on downloads for tasks traditionally done online,” the blog post states. The firm emphasizes that many legitimate services can convert files directly in the cloud without requiring additional software installations.
Malwarebytes advises anyone seeking file conversion services to verify the legitimacy of the platform before downloading any executable files. Experts also recommend keeping antivirus software updated and avoiding suspicious websites.
