Major Internet Threat: Poisoned PDF Files and How to Protect Your Computer

By Jim Roberts | News

pdf_corruptedReports from several major security companies show that corrupt or poisoned PDF files are now in the list of internet security threats. These suspicious files have increased in numbers in 2009 and made up a staggering 49% of all attacks in the Internet.

This percentage increased from 11%, second only to the corrupt PDF files is the Internet Explorer browser flaw.

So how does a normal attack happen?

Internet hijackers get into a legitimate site by inserting a poisoned PDF file to a link that masquerades as a social media ad or spam comments in a blog. Even the most tech and internet-savvy user can be fooled. They end up clicking that link then downloading and opening the bad file.

The threat is inside a PDF file. It comes in the form of a malware that opens and automatically installs by opening the PDF file. This was discovered by Didier Steven, and he also found that the Internet attackers fool unsuspecting users.

This web-based attack is extremely dangerous as it is built to take over the standards of PDF programs. This means that it not only attacks Adobe Readers but PDF readers as well. Even new and up-to-date versions are not safe.

The creators of the Zeus Trojan horse viral software are already using the same techniques to propagate their software.

How to Protect Your Computer against PDF Virus

Don’t fret as you can fight this form of web-based attack. Go to Preferences option in your Adobe Reader. Click on Trust Manager and uncheck the option for “Allow Opening of Non-PDF file attachments with external Applications”.

You can also opt to use the latest version of the Foxit PDF reader. It has a new safe reading feature which can be found in the Trust Manager section in Preferences. This special feature blocks the embedded programs from opening or installing.


Also, the most common attacks from these poisonous PDF files happens to users of Adobe PDF, you can avoid an attack by using an alternative version of the PDF program. Opt to use the latest versions as well. The internet hijackers have already mastered the ins and outs of the basics functions of the Adobe PDF programs and PDF readers that the older versions are surely not safe from the threat. In fact, when the threat first occurred, Foxit was not able to prevent it and these bad programs continued to run. Adobe and Foxit are now continually making more security measures to combat this web-based attack.

As a last note, make sure that you have a great anti-virus program installed in your computer. You can check out the best free antivirus programs we have mentioned. When it comes to the web, make sure you know what you’re doing 🙂

About the Author

Holding a dual degree in both Management and IT with 13 years of business experience, I am Jim F. Roberts from California, USA. Needless to say, I am a techy guy and I love exploring, checking out the latest gadgets and sharing my thoughts on a lot of things.