A person sitting at a kitchen island and working on their laptop

Adobe Acrobat

Ensure your PDF files are safe from viruses.

Like other software, PDF files can hide viruses and malware or be used by bad actors. Explore ways to defend yourself. 

Can PDFs have viruses?

Yes. Because PDFs are one of the most universally used file types, hackers and bad actors can find ways to use these normally harmless files — just like dot-com files, JPGs, Gmail, and Bitcoin — to create security threats via malicious code.

Understanding how PDFs can contain viruses.

Security threats come in a few main varieties. Viruses are programs that might do nothing, or change or delete data. Trojans usually gather data on a user or their computer. Malware is usually designed to harm a machine.

 

Viruses, Trojans, and malware have many ways of hiding inside a PDF, and often show up in email downloads or attachments like eBooks and other documents. They usually come from unknown or unfamiliar senders. 

Someone checks a pdf at a kitchen counter

You can defend yourself against viruses and other attacks through best practices, good judgment, and constant vigilance. Protect yourself by learning about the most common issues, including:

JavaScript

JavaScript is a programming language that supports functionality on the web. Most websites and web browsers have some kind of JavaScript element that’s used to execute code. PDFs, like other file formats, can have hidden JavaScript code that might exploit vulnerabilities in a PDF.

System commands

Opening a malicious PDF can launch malware that will start up whatever process the hacker has in mind. That is, by clicking on and opening a PDF or other file, a user also unknowingly starts up a predator program. Such attacks are technically possible today, but less common.

Hidden objects

Hackers try to circumvent antivirus and anti-malware software. Files and email attachments can have embedded or encrypted objects which prevent detection by cybersecurity measures or users. Usually, these hidden objects are executed when the file that hides them is opened.

Get work done. Anywhere.

Acrobat logo

Adobe Acrobat Pro

How to defend against PDF viruses.

There are many proactive ways to protect against hacking. Effective ways to defend yourself include:


1. Recognizing phishing attempts.

If you get a suspicious email that says it comes from a trustworthy-seeming organization like a financial institution, don’t engage with it. Reach out to that financial institution directly and ask if that email is real. That way, you can stay protected by never engaging with the email in the first place.

 

It can also be useful to use authentication methods for trusted collaborators and only engage with files that come from trusted sources. Adobe Acrobat Sign includes a feature for identity authentication.


2. Using a trusted PDF reader.

One of the best defenses against PDF viruses is to use trusted software and keep it up to date. There are many  PDF viewers, but not all of them are constantly updating to combat bad actors and help protect users. Adobe Acrobat Reader features regular security updates and is the industry standard for viewing and using PDFs.


3. Running regular virus scans.

Most operating systems like Windows and MacOS have built-in antivirus software. Third-party cybersecurity programs are usually redundant, but it’s still a good idea to regularly check your OS antivirus scanner. 


A person standing at a kitchen counter eating from a bowl while reading their tablet

PDF documents and phishing.

How do viruses, malware, and other nasty weapons that hackers use actually get on someone’s computer? The answer is a practice called phishing.

 

Phishing is when hackers make their emails appear as if they come from a familiar brand, a government agency, or other benign source. The victim then downloads a file or goes to a website that they think is from a trusted source, but there’s almost always a tell in phishing emails. Something might be slightly off, or it could come from an address that is clearly not correct.

 

So, can PDFs have viruses? They can, and they can look like a suspicious message with an attachment about your car insurance, but you don’t actually have a car. If so, you’re almost certainly looking at a message from a hacker who’s trying to dangle bait in front of you.

Stay safe with Adobe Acrobat and security.

Adobe Acrobat and Adobe Document Cloud include security features to make PDFs more secure and reliable.

 

To tap into additional virus and malware protection, you can:


1. Configure Acrobat not to launch non-PDF attachments with external applications.

Even if you accidentally download a malicious attachment, it’s possible to keep it from launching by default. 


2. Adjust or disable JavaScript in Acrobat to further protect against vulnerabilities.

JavaScript code is a common hiding place for viruses. Acrobat allows users to adjust JavaScript behavior so that it executes only within a specific, desired level of security. It is also possible to disable JavaScript altogether, or add restrictions.


3. Use Adobe cloud storage for your PDF storage.

Adobe cloud storage uses up-to-date industry-standard security practices to protect data,safeguard documents, and better shield important information from malicious actors.


It will always be possible for PDFs, like any other type of document or bit of code, to carry viruses, malware, or tools for hackers. However, by taking these measures to defend yourself and relying on proven software, you can make it less probable that any attacks succeed.

Acrobat logo

Do more with Adobe Acrobat Pro.