Flaw in WordPress caching plug-in could affect over 1 million sites

Attackers could exploit the vulnerability to inject malicious code into WP Super Cache admin pages, a researcher found

A vulnerability in the popular WP Super Cache plug-in for WordPress could allow attackers to inject malicious scripts into websites. The scripts, when loaded by administrators, could trigger unauthorized actions.

WordPress websites are a popular target for hackers and many of them are compromised due to plug-in vulnerabilities. Just on Tuesday, the FBI warned that attackers sympathetic to the extremist group ISIS -- also known as ISIL -- have defaced many websites by exploiting known vulnerabilities in WordPress plug-ins.

The persistent cross-site scripting (XSS) flaw in WP Super Cache can be exploited by sending a specifically crafted query to a WordPress website with the plug-in installed, according to Marc-Alexandre Montpas, a senior vulnerability researcher at Web security firm Sucuri.

The attack could be used to inject malicious scripts into a page that lists the files cached by the plug-in, and which is accessible only to administrators. As such, in order for the malicious code to be executed, the page must be viewed by an administrator.

"When executed, the injected scripts could be used to perform a lot of other things like adding a new administrator account to the site, injecting backdoors by using WordPress theme edition tools, etc.," Montpas, who found the vulnerability, said Tuesday in a blog post.

WP Super Cache can be used to optimize WordPress sites by converting dynamically generated pages into static HTML files that are then served to visitors. This can be very helpful for websites that receive a lot of traffic, because it reduces server resource and bandwidth consumption.

However, replacing PHP-generated pages with static, cached copies has its downfalls. The biggest one is that whenever there are changes to a page, the corresponding cached file needs to be regenerated.

As outlined in an older bug entry, after making tweaks to a page, administrators might need to look at the list of cached files to know which one to delete. So, the administrative action needed to exploit the vulnerability found by Montpas is not uncommon.

According to statistics from the official WordPress plug-in directory, the WP Super Cache plug-in has over one million active installations. In order to be protected, WordPress site owners should upgrade the plug-in to the latest version -- 1.4.4 at the time of this article.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags online safetyintrusionpatchesExploits / vulnerabilitiesSucuri

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Lucian Constantin

Lucian Constantin

IDG News Service
Show Comments

Essentials

Brother MFC-L3745CDW Colour Laser Multifunction

Learn more >

Mobile

Exec

Budget

Back To Business Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?