Regardless of the format, several hackers and phishers are out there creating a virus or malware that results in chaos. While PDFs are one of the safest formats to save and share documents on the Internet, they can contain viruses. It might be in different codes and forms, including malware hidden in JavaScript codes or hyperlinks. Typically, you may receive a virus-infected PDF from suspicious or unknown senders, web content, and downloads. But viruses or malware will only affect your computer after clicking or opening the file.
So, while viruses in PDF can be a scary thought, you can quickly check for hidden malware to safeguard your computer. There are four types of malware hidden in PDF documents and emails. It can be in multimedia, hyperlinks, JavaScript, and codes. In this guide, you will learn if your PDF document is infected with any of these viruses and malware.
- Multimedia (images, audio, videos, etc.)
PDF documents may contain flash, images, audio, videos, and multimedia. Users are likely to download or play to view this content. However, each multimedia element may contain viruses, and the elements might be corrupted. So, when users download them, malware or virus might overtake the computer without the user’s knowledge. You must have antivirus software installed on your system to scan the PDF documents before downloading any multimedia elements within the files.
- Hyperlinks
PDF documents typically contain hyperlinks and links that allow users to jump from one section to the next. It allows users to navigate through web pages and resources simultaneously easily. It is considered the norm to see such links within a document. However, these are also avenues for cybercriminals and hackers. Clicking on such hyperlinks or links might take you to malicious websites and manipulate your computer. The links may ask you to download unwanted files, which may steal your information.
Antivirus software will scan the links but to ensure it does not lead to something malicious, you must do a manual check. Hover the cursor over the hyperlink, and an alt text will appear. The sender is honest with the sources if the text is the same as the link’s destination. But you must also note that most cyber criminals purchase credible-looking domain names, so you must do your research before clicking on the link.
You should not trust a web address found encoded in the content. It always leads to another website with malware or virus.
- Codes or Programming
Codes are a significant part of files and programs that execute commands. A virus is also a code that executes a command. So, if the PDF document is encoded with viruses, it will execute commands to harm your computer. It may modify the computer programs using its code. If you use unreliable readers to open a PDF document, you are making it easier for the command to infect your computer. So, you must always use Adobe Acrobat Reader to open and view PDF documents.
Adobe will protect your computer from command-based viruses. You must remember to update the Adobe PDF reader to protect your computer against malicious PDF documents. If the reader is updated, it would mean the vulnerabilities of the reader are fixed, and viruses will find it harder to break into your computer. You must update the reader from the app and don’t trust ads.
- JavaScript
Like HTML, JavaScript is a computer language for coding, and you can use this to create interactive elements and graphics that focus on interface and function. It helps readers quickly navigate and go through a website as user-friendly. In PDF documents, JavaScript might be embedded, and it can commence viruses on your computer.
By disabling JavaScript in your PDF reader, you can avoid such attacks. You can also scan the documents using antivirus software. You can turn off JavaScript in Adobe Reader by opening Adobe Reader > Edit > Preferences > JavaScript > untick the box for Enable Acrobat JavaScript > click OK. The settings will be saved.
The Bottom Line
You can know if your PDF document is infected with viruses or malware if you scan the document and use a reliable reader like Adobe Acrobat Reader to open PDF documents. For your safety, you must not open a document sent by suspicious or unknown senders. If you do not know where the document came from, it is best not to open it and download it to your computer.
It is also a good habit to use antivirus software to scan the document before you open the file. Scanning the files will inform you if it is safe to open the PDF document. You must also regularly update your computer to be equipped with the latest security features and bug fixes. You can go to settings and update the OS software to keep your computer safe. All the best!
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