FBI Warning: Stop Using Free Online File Converters | A Growing Malware Threat

Key takeaways

• Fake converter sites copy real tools with slightly changed URLs and deliver malware or steal files.
• Use trusted desktop software or built-in features to convert documents instead of random web tools.
• If you used a suspicious converter, change passwords and scan the device.

Table of Contents

• What is the FBI Warning About?
• How Do Malicious File Converters Work?
• List of Malicious File Converter Websites Identified
• How Are These Malicious Websites Used in Cyber Attacks?
• How to Protect Yourself from These Attacks?
• Why This Threat Matters
• Conclusion

Cybersecurity threats are evolving rapidly, and the FBI has recently issued a critical warning for Google Chrome, Microsoft Edge, and Apple Safari users. The warning highlights a growing cyber threat in which free online document converters are being used to distribute malware, leading to ransomware infections, data theft, and unauthorized system access.

In this blog, we will explore the details of this FBI alert, how these malicious websites operate, the risks involved, and what users can do to protect themselves.

What is the FBI Warning About?

The FBI has confirmed that malicious file converter websites are being used to distribute malware. These websites mimic legitimate services but instead infect users’ devices. Cybercriminals create these fake converter tools with slightly altered URLs to make them appear authentic.

Many people search for free tools online to convert PDFs, images, or MP3 files. However, the FBI has warned that these sites are being leveraged to push malware onto victims' computers, which can lead to:

• Ransomware attacks

• Credential theft

• Data breaches

• Unauthorized access to sensitive files

How Do Malicious File Converters Work?

1. Search Engine Manipulation

Cybercriminals promote these malicious websites using paid ads on search engines. When users search for "free online file converter," these ads appear at the top of search results, making them more likely to be clicked.

2. Fake Websites That Look Legitimate

The fraudulent sites use minor URL changes to resemble real file converter services. For example, a scam site might be named:

• Imageconvertors[.]com (instead of "imageconverters.com")

• Convertix-api[.]xyz (instead of "convertix.com")

3. Malware Installation Upon File Conversion

Once a user uploads a file for conversion, the site delivers an infected file back to the user instead of a clean converted document. This file may contain:

• Trojan malware

• Phishing scripts

• Adware

• Ransomware payloads

List of Malicious File Converter Websites Identified

Cybersecurity researchers and threat intelligence teams have already identified several fake file converter sites distributing malware:

• Imageconvertors[.]com - Phishing

• Convertitoremp3[.]it - Riskware

• Convertisseurs-pdf[.]com - Riskware

• Convertscloud[.]com - Phishing

• Convertix-api[.]xyz - Trojan

• Convertallfiles[.]com - Adware

• Freejpgtopdfconverter[.]com - Riskware

• Primeconvertapp[.]com - Riskware

• 9convert[.]com - Riskware

• Convertpro[.]org - Riskware

If you have used any of these websites, scan your system immediately with an updated antivirus tool.

How Are These Malicious Websites Used in Cyber Attacks?

1. Spreading Ransomware

Reports suggest that ransomware gangs are leveraging these fake file converters to compromise corporate systems. A recent ransomware attack in Iowa was linked to this attack vector.

2. Stealing User Credentials

Malware-infected files can contain keyloggers that record keystrokes and steal usernames, passwords, and banking information.

3. Exploiting JavaScript and Macros

Even if the conversion seems successful, embedded malicious JavaScript in PDF files or Visual Basic macros in Word documents can execute as soon as the file is opened.

How to Protect Yourself from These Attacks?

1. Stop Using Online File Converters

The FBI advises users to avoid online file conversion services altogether. Instead, use trusted software such as:

• Adobe Acrobat (for PDFs)

• Microsoft Office (for Word and Excel conversions)

• Cloud-based services like Google Drive and OneDrive

2. Verify Website Authenticity

Before using any website:

• Check the URL carefully for slight spelling changes.

• Look for HTTPS encryption in the address bar.

• Search for reviews and user experiences before trusting a site.

3. Use Ad Blockers and Avoid Clicking on Sponsored Ads

Cybercriminals push malicious file converters through paid advertisements on Google and Bing.
Use ad blockers like uBlock Origin to reduce exposure.

4. Keep Your Browser and Security Software Updated

Always update Google Chrome, Microsoft Edge, and Apple Safari to patch vulnerabilities.
Install a trusted antivirus like Bitdefender, Norton, or Malwarebytes.

5. Scan All Downloaded Files for Malware

Before opening any downloaded file, scan it with an antivirus tool.
Use Windows Defender, Kaspersky, or ESET for file scanning.

6. Enable Multi-Factor Authentication (MFA)

Even if your credentials get stolen, MFA can prevent attackers from accessing your accounts.

Why This Threat Matters

Cybercriminals are constantly evolving their attack methods, and online file converters are just the latest in a long list of cyber traps. As ransomware attacks and AI-driven cyber threats become more sophisticated, users must be extra cautious when downloading files from unverified sources.

Key Takeaway: If you see a free online file converter website, avoid it. Stick to trusted apps and built-in document conversion tools.

Conclusion

The FBI’s warning about online file converters is a serious cybersecurity concern. Malicious sites disguised as free tools can spread ransomware, steal credentials, and compromise devices. Users should stop using online converters, rely on trusted software, and always scan downloaded files.

By staying informed and adopting safe browsing practices, you can significantly reduce the risk of falling victim to these cyber threats.

To take this further with guided labs and an instructor, see our our cyber security classes.

Related reading

• FTP Search Engines | How Cybercriminals and Researchers Use FTP for Information Gathering and How to Secure FTP Servers
• Mastering Google Hacking | Advanced Search Operators and Exploit-DB for Cybersecurity and OSINT
• Malware Threats in 2026 | Latest Types, Attack Trends, and Protection Strategies

Reference

For the authoritative details, see CERT-In (India).