What makes the PDF so enticing to malicious users? There are more reasons than you think.
With the recent headlines about Adobe PDF vulnerabilities being taken advantage of, just about anyone who used a PC was on the alert. PDF files have the potential to do some serious damage to systems and data when infected.
Because the PDF is not without its weaknesses, anticipating ways in which attackers can use the format can be the best way to defend against it.
Below is a brief look at 13 ways—both technical and simple, in which the PDF is vulnerable and can be manipulated by malicious users.
1) JavaScript
Online PDFs are designated with open parameters that can be injected with malicious JavaScript code. Because of the flexibility of JavaScript, hackers have a broad range of what can be done using the PDF file as their hacking tool of choice.
2) Spam
The recent spamming attacks this year demonstrated a way of exploiting the nature of the PDF as file format. Until recently, the PDF never really got caught at the anti-spam gates. Thus, although most anti-spam products now check PDFs and other forms of image spam, PDF containing spam made it into millions of inboxes everywhere. Although not immediately threatening as code executions, spam is still spam and has the ability to deliver Trojans, viruses, and malware.
3) PDF Ubiquity
PDF files are perfect for spreading attacks far and wide. The ubiquity of the PDF makes this possible. The number of PDF files on the web alone is an example of what the odds are of being hit by an infected PDF.
4) PDF Hyperlinks
As with most spam, the attacker’s malware doesn’t just sit within the PDF file. Rather, it is through the embedded hyperlinks within the PDF that launches it.
5) PDF Credibility
The PDF is known as secured standard format used by many business industries and users alike. As such, hackers can accomplish their task easily by turning users into malware executioners. Just by thinking that your PDF attachment or download is safe and secure, the attackers’ work is done.
6) Browsers and PDF URIs
PDFs are also manipulated because of the way in which their URIs are handled by certain web browser applications. Websites that host PDF files are unknowingly cohorts in the attack. XSS, for instance, uses a flaw in the browser that triggers an unintended execution of code as part of a query string contained within the URL. Although the browsers that contained this URI validation flaw were patched up with the last software version updates, this single flaw put every user with those browsers at risk.
7) PC Software
Because a PDF’s URI can be crafted with malicious JavaScript code, it can take advantage of applications that are installed on a PC. The open parameters within PDF URIs allow commands to be sent to the program when the file is opened. The most commonly installed software on computers, such as PDF viewers, are targeted because of this integration with the OS.
8 ) PDF Usage
Essential to business industries and government agencies, PDF usage goes hand in hand with the format’s ubiquity and credibility. Being transmitted, viewed and stored between databases that hold sensitive and confidential information, the PDF format makes an ideal format for attackers to use.
9) Lack Of Security Settings
Obviously, on the more simple PDF creation level, a lack of PDF security settings makes all the difference. The PDF content itself is vulnerable to being manipulated without customized file usage restrictions, passwords, high encryption strength, and digital signatures. The basic one step PDF creation process isn’t a strong defense when it comes to protecting your PDF content.
10) PDF As An Email Attachment
Something wrong always happens when it comes to emailing a PDF. When receiving a PDF file via email, the PDF is first stored before it can be opened in a designated viewer. Needless to say, attackers use this characteristic process to execute their attacks from the local host.
11) PDF Specification
Having the PDF specification published makes it easy for developers to create third party tools for the PDF format and its software applications. However, it also means that it’s easy for attackers to generate malevolent uses for the PDF and develop work-arounds to manipulate regular PDF functionalities.
12) User Habits
Another reason why hackers target this format is simply because not many people update their PDF software on a regular basis. While attackers try to find weak spots in the latest software, their past work can still do damage on systems via PDF applications that haven’t yet been updated.
13) PDF Features and Functions
The PDF imports and integratesmany functionalities that make it inherently vulnerable and prone to exploitation. The more the PDF format advances in form and function, the more opportunities there are for exploiting the format.
As more PDF related flaws are being exploited quicker than they are being patched, it’s important to keep an eye out for these things as nothing digital is ever completely safe.