How do I get Foxit Reader to let me click on links?

PDF format has become the latest target for malware. As it turns out, there
are assorted vulnerabilities in various PDF readers, as well as in the very
definition of PDF format itself. Hackers are creating malicious PDF documents
in an attempt to infect your computer with malicious software.

The net result is that PDF readers have begun implementing various security
measures to allow you to read PDF documents in safety.

“Safe Mode” is one such measure in Foxit Reader.

It’s easy to turn off and I’ll show you how. I’ll also discuss the threat
that it’s protecting you from.

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The Problem

The problem that we’re facing is a very simple one. Much like web pages, PDF documents can include links that go to other web pages on the internet. When you click such a link, the PDF reader may inform you that it’s disallowed:

To quote:

In safe reading mode, this document does not allow connection to:
https://go.askleo.com/procmon If you want to enable this function, please check the Trust Manager preferences to disable safe reading mode.

That’s after an attempt to click one of the links in my Maintaining XP guide.

Disable this “safe reading mode”? We can do that.

Disabling safe reading

In Foxit Reader, click the Tools menu, the Preferences menu item, and then the Trust Manager sub-item in the left column:

As you can see, the Trust Manager has exactly one option:

Un-check Enable Safe Reading Mode, and click OK. Now, when you click a link, you’ll get a simple warning that will allow you to proceed:

Click “Yes” and your web browser will open on the link shown.

What am I getting myself into?

Disabling something called “safe” reading mode implies that you’re doing something that’s not safe.

Kinda sorta, but not really.

As you can see when safe mode was disabled, you weren’t prevented from clicking the link, but you were warned, with a clear indication of the destination of the link. Rather than having your PDF reader trust no one, it’s now up to you to know who to trust.

The “problem” is that PDF files do more than open pages in your web browser.

Foxit’s own words around the safe reading mode option:

Foxit recommends that you check this option for controlling unauthorized actions and data transmissions; including URL connections, launching external files, and running Javascript functions to efficiently avoid attacks from malicious documents.

As I’ve said, PDF is a powerful format. With that comes risk. PDF documents can:

• Make URL connections – which means opening up your web browser to a web page. Unless you have the opportunity to examine the URL first, a malicious document could take you to a malicious web site.

• Launch external files – which means clicking a link in a PDF document could run a program on your machine. Perhaps a malicious program, perhaps a standard program used in a malicious way.

• Run Javascript – just like in your web browser, Javascript can be included in PDF documents and can be used for good … or evil.

The fact is that Foxit’s safe reading mode is, perhaps, a bit of overkill as it disables all of these at once. That’s unfortunate in my opinion, because allowing clickable links is quite common, whereas running programs or Javascript, while possible, is rarely seen in actually PDF documents. I’d love to see an option to ONLY allow clicks – with a preview – to http: URLs and leave the other items disabled.

Next Steps

If you regularly receive documents from sources that you trust and you have the ability to evaluate any suspicious actions if the reader warns you about them, then I’d feel safe disabling this option. As you can see, it’s required to enable clickable links in PDF documents.

If you’re interested in learning a little more about PDF format and why it’s so popular, have a look at Just what is PDF format, how do I view it, and why do people use it?

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