Can You Get A Virus From A PDF?

Introduction

Adobe Systems Inc. designed the Portable Document Format (PDF) in the 1990s for the sole purpose of sharing documents. This incredibly creative and innovative file sharing system features many basic and advanced elements that make the entire process much easier than ever before. Using a PDF reader such as Adobe PDF Reader or Nuance PDF Reader will allow you to access PDF files easily and securely.

PDF files usually consist of text and graphics, but they might also contain various other types of content including elements such as logical structuring, annotations and form-fields, video content, and three-dimensional objects. PDFs also allow you to execute any type of code on to your device.

PDF still remains a popular and widely used file format for sharing documents, including text and images. We use PDFs for a lot of purposes, including business proposals, product reviews, legal and official documents, and even books. They are favored over other file-sharing methods due to their convenience and the extensively rich content they have to offer.

Many people are of the opinion that PDF files are a basic and innocent method of document sharing just because they contain words and images, and hence they must be safe. However, alongside this popularity there come certain serious disadvantages and security risks. PDF files are a popular target for malware attackers and can sometimes be vulnerable to infection by viruses.

People commonly send them as email attachments and so attackers and cybercriminals use PDF files to breach computer networks, install malicious content, and access private information. There are a number of ways you can prevent this from happening and this article mentions the most effective ones.  

Can You Get a Virus From a PDF File?

PDF files feature rich content including static and dynamic elements to provide an efficient and interactive document for quick file sharing. These dynamic features make these files vulnerable to malicious content and viruses. PDF files also feature embedding and allow you to execute code on your device; this feature in turn makes them highly risky as it exposes the files to interception by cybercriminals and can lead to malicious scripts being easily embedded in them.

JavaScript is often used for malicious intent such as infecting viruses and malware into computer systems and other devices. It can also include encrypted and embedded items, which prevents antivirus scanners from detecting malicious content and allows the items to remain hidden. When a user opens the infected file, the items are executed and malware is installed on to the device. The malware disrupts the device’s system and grants its creator access to the user’s credentials and personal information, which they could use for hostile criminal activities.

PDFs are the most common type of email attachments these days and you are very likely to come across one at some point. We recommend always using a secure PDF reader and staying vigilant whenever you download or share a PDF file. Malicious attackers and cybercriminals commonly target emails and drive-by downloads on some websites to implant malware and viruses, and people unknowingly download them – which exposes their system to attack and infection. It is important to note that PDF file attachments are not always vulnerable but some of them can contain viruses or other concealed malware; this is why you should always scan the PDF file before opening it or downloading it on your device.

How Can Your System Get Infected by a PDF File?

PDF file viruses are usually found in email attachments and drive-by downloads on websites that contain malicious content. The virus mainly spreads when these files are downloaded and shared with other devices. The virus or malware masks itself inside the PDF file and makes it appear normal and secure. The virus blends in and it can go unnoticed for a long time unless you have a good anti-malware protection system installed.

Advanced malware can even mask itself from anti-virus protection applications and software. When an infected document is downloaded and opened, it appears like a perfectly normal document with an option for enabling editing. In some cases, when you click on “enable editing”, you are redirected to a page that asks you to enable editing through a social engineering threat that downloads malware on your device. Your system can get infected with a virus if you open or download a PDF file from an untrusted source or person without scanning it properly beforehand.

How Can You Tell If a PDF File Contains a Virus?

If you care about your device’s protection and your privacy, you need to scan every PDF file before accessing it, especially the files you receive from unknown sources and people. There are several ways to check if a PDF file is infected by viruses and other malware before downloading it.

Firstly, you can upload the PDF to VirusTotal to scan for viruses. VirusTotal works by analyzing and identifying files and URLs to detect viruses, trojans, and other kinds of malicious content. It alerts you in case a file with malware is detected. However, the results are not fully accurate and you still need to be careful and cautious. Some email providers, like Gmail, contain built-in malware scanners for attached PDF files that alert you in case a file is marked as unsafe.

Secondly, you can scan the PDF file online using virus scanners such as PDF Examiner. PDF Examiner analyses all PDF files and JavaScript complications and scans for viruses and other malware. It can also be used for encrypted files.

Lastly, it is very important to use an anti-malware protection system on your device; this will scan your device for any viruses that potentially entered your device from an infected PDF file. Install a good anti-malware software on your device for optimum security and protection and keep it updated regularly for maximum performance and results.

How Can You Protect Your Device From Viruses in PDF Files?

Strong web and email filters provide some defense against PDF viruses and other malware. These filters reduce the number of suspicious PDF files that enter the system; however, they do not provide full security and protection as advanced viruses and malware are adept at hiding themselves. You must always be cautious before downloading a PDF file and you should make sure to use IPS, Anti-Virus, and sandboxing technology to scan and detect any hidden viruses or other malware in your PDF files.

Here are a few steps that you can take to ensure your device’s security:

• You can deactivate JavaScript on your PDF file reader. If you use Adobe Reader, you can disable Javascript by opening the reader, going to “Edit – Preferences”, or by simply pressing CTRL + K. Next, select Javascript and untick the “Enable Acrobat JavaScript” option; this will disable Javascript from your PDF reader and will prevent malicious files from being downloaded.
• You should never enable your PDF reader to launch non-PDF files by using an external application or software. If you use Adobe Reader, go to Preferences, select “Trust Manager”, and restrict external applications from launching PDF files.
• You should always disable macros. Microsoft intentionally disabled the auto-execution of macros as a security measure a long time ago, and for a good reason. Some malicious files try to convince you to enable them; however, you must always keep them disabled.
• You should deactivate the startup entries of PDF readers from Window’s startup programs. This protects your device from future threats on PDF readers and it also reduces Window’s boot-time process.
• You should never access or download file attachments sent by untrusted and unknown people or sources. You should always read the name of the file and its sender before opening it on your device. Gmail automatically scans all email attachments and blocks suspicious files that might contain malicious content. It is advisable to only open and download files from trusted sources and people you know. However, if you do want to access an unknown PDF file, you should remember to first scan the file for viruses and malware.
• Always remember to keep your Windows, PDF reader, and Anti-virus software updated.
• You should keep all your PDF files encrypted and back them up routinely if you do not want to lose them to hackers, viruses, or cybercriminals. This will ensure that all your information and data remains confidential in case your device is infected or gets stolen.

Conclusion

Whether a file is vicious or not does not only depend on the file extension, but also depends on the susceptibilities and vulnerabilities of the software that will be deciphering it. For instance, the PDF reader you use could possibly contain a buffer overflow vulnerability, allowing hackers to construct special PDF files to take advantage of this weakness. You can ultimately protect your device by always keeping your software and anti-malware protection system updated and by never downloading files from unknown sources.