The Promise & The Peril of HTML5

Posted by Kevin Poniatowski on June 26, 2017 at 12:30 PM

Like many software engineers, I love new toys. New programming languages allow us to create new features quickly, while handling tedious overhead issues, making it so we don’t have to think about them.   However, in this desire for using the “new,” developers often forget to ask themselves, “How do we secure it?” Each feature of a new development tool may have security issues that we need to be aware of.  However, in the rush to create, we don’t always educate ourselves thoroughly about the risks of those features.  For example, HTML5 is becoming more popular now that all current browser versions support it, but developers need to be aware of the security issues they may encounter when utilizing certain HTML5 features.  

Offline Storage
What developer doesn’t want to take advantage of more storage space on the browser?!  This enables us to store persistent user data.  However, just like Spiderman’s Uncle Ben said, “With great power comes great responsibility.”  Developers needs to make sure that the data they are storing in the browser isn’t sensitive.  Storing data that is considered sensitive by HIPAA, GLBA, or SOX regulations could result in severe legal ramifications and storing sensitive PCI data could lead to hefty fines.  Developers must be made aware of what data is ok to store and which data should never be stored in the browser.

HTML5 gives us the ability to determine a user’s location and use that information to tailor search results, push notifications to the user about deals near them, and lots of other cool features.  However, developers need to be very careful about using geolocation because many end-users may not want their location to be used.  They may consider their location to be sensitive information that they don’t want distributed.  The geolocation functionality could easily be abused by malicious websites tracking users for nefarious purposes. 

Cross-Site Scripting
While many web developers are aware of cross-site scripting, they may be unaware that using HTML5 creates a new unfamiliar attack surface.  Each new feature within HTML5 such as local storage, canvas, and video capabilities could be implemented insecurely, giving an attacker the ability to run malicious scripts within the browser.  Developers still need to carefully sanitize any input from one user that will be sent as output to other users in order to lower the risk of that output becoming malicious.

The thrill of using new tools and new programming languages will always attract developers.  But we must get educated about securing any new functionality from these tools and languages before applications go into production.

If you want to learn more about HMTL5 security implications and how to write more secure HTML5 code, join me as I present the HTML5 Security – The Promise & The Peril webinar on July 12th at 1:00pm ET.

Topics: developer guidance, application security, html5

Kevin Poniatowski

Written by Kevin Poniatowski

Kevin brings an optimal blend of speaking ability, technical savvy, and an insatiable passion for security to Security Innovation's training customers. This produces an engaging and enlightening environment from which to deliver both technical and awareness courses. Kevin entered the application security field in 2007 with Security Innovation, where he has split time between application security course development and delivering instructor-led courses. Kevin is a Senior Security Instructor and Engineer at Security Innovation.