A jQuery 1.x vulnerability exists and no fix is planned

I haven’t seen much talk about this issue around the Internet, so I thought I’d present what I’ve learned for others to be aware of. It mainly has to do with the fact that jQuery 1.x (and 2.x, for that matter) were replaced by 3.x, yet they are still thriving in many, many projects, applications, and websites to this day.

While doing a security review of some code the other day, a retirejs scan informed me that jQuery 1.x contained a Medium vulnerability regarding cross-domain requests in ajax. According to Snyk:

“Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks when a cross-domain ajax request is performed without the dataType option causing text/javascript responses to be executed.

Remediation: Upgrade jquery to version 3.0.0 or higher.”

“Upgrading to 3.0.0 or higher seems pretty drastic,” I thought to myself. Well, according to a comment I found on jQuery’s GitHub page, this is actually their stance, and they don’t plan on patching 1.x because it is a ‘breaking change’:

https://github.com/jquery/jquery/issues/2432#issuecomment-290983196

So it would behoove you to upgrade to jQuery 3 if you don’t want to be susceptible to this vulnerability. The magnitude of that may seem rather staggering if you consider all the projects across just about everything (WordPress plugins, Drupal modules, etc etc) that bundle the 1.x version of jQuery, and haven’t updated it in years.

While the vulnerability may not be relevant if you are not making cross-domain ajax calls, this is but one risk that has come to light for which there will be no fix. And it’s not exactly reasonable to assume that developers know they need to avoid that if they intend to use jQuery 1.x.

The longer jQuery 1.x sits in your project, the higher a risk it becomes.

As the impending OWASP Top-10 for 2017 says, “Applications and APIs using components with known
vulnerabilities may undermine application defenses and enable various attacks and impacts.”

Long story short: Keep your bundled libraries up to date!

About Will Chatham

Will Chatham is an Information Security Analyst, OSCP, Ethical Hacker, and Penetration Tester at a federal data center in Asheville, NC. Since Netscape 2.0, he has worked in a wide array of environments including non-profit, corporate, small business, and government. His varied background, from developer to search engine optimizer to security professional, has helped him build a wide range of skills that help those with whom he works and teaches.

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