Serious flaw fixed in widely used WordPress plug-in

The persistent XSS vulnerability could allow the hijacking of admin accounts

If you're running a WordPress website and you have the hugely popular All in One SEO Pack plug-in installed, it's a good idea to update it as soon as possible. The latest version released Friday fixes a flaw that could be used to hijack the site's admin account.

The vulnerability is in the plug-in's Bot Blocker functionality and can be exploited remotely by sending HTTP requests with specifically crafted headers to the website.

The Bot Blocker feature is designed to detect and block spam bots based on their user agent and referer header values, according to security researcher David Vaartjes, who found and reported the issue.

If the Track Blocked Bots setting is enabled -- it's not by default -- the plug-in will log all requests that were blocked and will display them on an HTML page inside the site's admin panel.

Because the plug-in fails to properly sanitize the requests before displaying them, attackers can inject malicious JavaScript code in the request headers, allowing the code to end up as part of the HTML page.

This allows for a persistent cross-site scripting (XSS) attack, where the rogue code will be executed every time a user views the log page. Because that page is in the admin panel, that user will likely be the administrator, and the code can steal their session tokens.

These tokens are values stored inside the browser that allows a website to identify a logged in user. By placing these values in their own browsers, attackers could access the website as an administrator without having to authenticate.

The rogue code could also force the administrator's browser to perform an action that they haven't authorized.

The All in One SEO Pack developer, a company called Semper Fi Web Design, has released version 2.3.7 Friday in order to fix this vulnerability. Users are advised to upgrade to this version as soon as possible or to make sure they don't have the Track Blocked Bots setting enabled.

All in One SEO Pack provides a lot of search engine optimization features meant to increase a website's visibility in search results. According to statistics from the WordPress plug-ins repository, it is popular, with over one million active installations.

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

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

Lucian Constantin

IDG News Service
Show Comments

Most Popular Reviews

Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?