The world of WordPress plugins is vast, offering millions of users great features—but sometimes, new features come with new risks. Among these risks was a vulnerability found in the Simple:Press forum plugin for WordPress. Officially tracked as CVE-2022-4029, this security flaw opened doors to Reflected Cross-Site Scripting (XSS) attacks against websites using affected plugin versions (≤6.8).

In this post, we’ll break down how the vulnerability works, why it matters, how an exploit might look (with code), and how you can protect yourself if you’re using Simple:Press.

What Is Simple:Press?

Simple:Press is a popular WordPress plugin that adds full-featured forums to WP-admin websites. It offers both free and paid options and is popular among community-driven sites that need a discussion board.

Attack Vector: Authless (no login required)

Issue: The plugin failed to properly sanitize and escape data taken from a cookie named sforum_[md5 hash of the WordPress URL]. If an attacker could set this cookie's value for a visitor, malicious data could be reflected into a website response and run in the user's browser.

Why Is This a Problem?

Cross-Site Scripting (XSS) lets attackers inject JavaScript code into pages viewed by other users. In reflected XSS, the attacker needs to make the victim send a specially crafted request to the vulnerable site—often done by tricking them into clicking a link. If the plugin echoes the _unsanitized_ data from a cookie into the page, a browser might execute whatever code the attacker included.

Defacing pages viewed by targeted visitors

The risk was somewhat limited: the attacker needs to make the victim have a specific cookie set before visiting the forum. Usually, JavaScript running on another site or some social engineering (like getting the user to click a special link) would be needed.

Exploit Example

Let’s walk through a hypothetical attack scenario.

The vulnerable cookie is named something like this:
sforum_[md5 hash of your WordPress site's URL]

Suppose your WordPress site's URL is https://yourdomain.com, and the md5 hash of this is 15767b9b49cd3c8f3a7c18d517ea99e7.

sforum_15767b9b49cd3c8f3a7c18d517ea99e7


document.cookie = "sforum_15767b9b49cd3c8f3a7c18d517ea99e7=<script>alert('XSS!')</script>; path=/";

Step 3: Trick the User

Either via a compromised site, a phishing email, or a direct message, the attacker tricks the victim into running this JavaScript in their browser, which silently sets the cookie for yourdomain.com. Next, the victim visits the forum page on your WordPress site.

Step 4: XSS Triggers

Because the Simple:Press plugin did not sanitize the value of that cookie, it outputs the script tag, which the browser immediately executes:

<script>alert('XSS!')</script>

Voilà! The attacker’s code runs in the victim’s browser.

PoC (Proof of Concept) using JavaScript Bookmarklet

A real-world attack, for demonstration or testing (on your own site only!), might look like this. You’d paste this bookmarklet into your browser bar, change the domain/hash as needed:

javascript:document.cookie="sforum_15767b9b49cd3c8f3a7c18d517ea99e7=%3Cscript%3Ealert('XSS!')%3C%2Fscript%3E; path=/";window.location.reload();

References and More Reading

- WordFence Advisory for CVE-2022-4029
- NIST National Vulnerability Database Entry
- Simple:Press Plugin Official Website
- OWASP: Cross-Site Scripting (XSS)

Why Was This Hard to Exploit?

This XSS wasn’t as easy as most, because the attacker needed to make the victim’s browser set a cookie for your site (which JavaScript normally can’t do cross-domain). However, if the attacker controlled another vulnerability (like a subdomain or an open redirect on your site) or used social engineering, they could potentially pull it off.

Still, any XSS, no matter how complex to exploit, is dangerous, especially on logged-in admin users.

How Can You Fix or Prevent This?

- Update Simple:Press: The plugin was patched in a later version, so updating to the latest version closes the hole.
- Set Secure Cookie Policies: Modern browsers block most cross-site cookie trickery, but setting your site's cookies with SameSite=Strict helps.
- Input Sanitization: Always ensure any plugin or theme you use is well-maintained and implements data sanitization before outputting user-influenced content.

Takeaway

CVE-2022-4029 highlights a classic web security lesson: always sanitize and escape everything that may end up in browser output, even data from cookies. The risk to Simple:Press users was real, if a bit complex for everyday attackers—yet sites left unpatched could pay a high price if targeted.

If you use Simple:Press, update immediately.

Have you spotted signs of this exploit in the wild, or want help testing your site’s XSS defenses? Feel free to reach out or hire a web security professional for a scan.

Stay safe out there!

*Written and researched exclusively for [your site/blog name].*

Timeline

Published on: 11/29/2022 21:15:00 UTC
Last modified on: 12/01/2022 18:39:00 UTC