Can PDF have Viruses? How to detect malware in the PDF Document

The PDF may contain viruses.

PDF is a convenient file format for document sharing. Consequently, it remains widely used for personal and official communication channels. Unfortunately, his admiration makes him a target for malware attackers. Although not always vulnerable and infected, some PDF files may contain viruses or other hidden malware.

As the most common email attachment, PDF is a frequent target of computer network breaches. Secure email gateways do not easily detect advanced PDF malware systems.

How are PDF files infected?

PDF is a powerful file that contains static elements (images and text), dynamic elements (forms), and embedded signatures. While these elements are necessary to make your listing visually appealing and consistent, they also have a downside.

The options above remain still used to inject malicious scripts. Javascript remains mainly used to infect the victim’s computer with malware. PDF files contain the ability to run code on your device – and therein lies the real danger.

Javascript –

Javascript is used in web coding to control the appearance and functionality of the browser. Unfortunately, it remained used to exploit various vulnerabilities in Adobe and many other PDF readers.

System Commands –

The run action in the PDF can open a command window and run commands to launch the malware. Most controls remain now disabled by Adobe but may remain open in other readers or older versions.

Hidden Objects –

PDF files may have embedded and encrypted objects that prevent them from being analyzed by an antivirus scanner. However, these objects remain running when the user opens the file.

Multimedia control –

When we say that a PDF can have embedded objects, it can be a fast media or a flash file. Thus, an attacker can exploit a security flaw in media players.

How to check for PDF viruses?

If you ever receive a PDF from an untrusted source, we recommend scanning the file before opening it. Email providers such as Gmail have a built-in malware scanner for file attachments. Plus, they implement VirusTotal technology so that you can be sure.

You can even scan the file with online antivirus programs before downloading. In addition, an online tool called PDF Examiner can analyze PDF files for Javascript obfuscation and other known exploits. It even works for encrypted files.

Finally, once you’ve downloaded the file to your computer, ensure you have real-time malware protection. It will be your next layer of defense to detect unknown malware and protect if something still goes wrong.

How to protect yourself from PDF viruses?

Disable JavaScript in PDF Reader: If you are using Adobe Reader, open Adobe Reader and go to “Edit -> Preferences” or press “CTRL + K.” Select JavaScript in the sidebar and uncheck the “Enable Acrobat JavaScript” box.

1. Do not allow the PDF reader to run non-PDF files with an external application.
2. Turn off the PDF reader from Windows startup programs.
3. Leave macros off. Malicious files may convince you to allow it, but you shouldn’t do it unless it’s necessary.
4. Do not download or open an attachment sent by an unknown email sender.
5. Ensure you have an up-to-date Windows operating system, PDF reader, and antivirus.
6. Back it up regularly and keep it encrypted.

Conclusion

Whether a PDF can contain a virus or not depends not only on file extensions. It also rests on the sensitivity of the software that will analyze it. For example, if the PDF reader you are using potentially contains a buffer overflow vulnerability, an attacker could create a separate PDF file to exploit the vulnerability.