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In late 2023, security researchers uncovered a serious vulnerability—CVE-2023-5051—in the popular *CallRail Phone Call Tracking* plugin for WordPress. This flaw enables authenticated users (like Contributors) to inject malicious scripts into websites using the plugin, putting site owners and visitors at risk.
This post dives deep into the vulnerability, explains why it happens, provides a sample exploit, and links you to original references for verification or further reading.
What is CVE-2023-5051?
In simple terms, CVE-2023-5051 is a Stored Cross-Site Scripting (Stored XSS) vulnerability in the CallRail plugin for WordPress (versions .5.2 and below). It arises because the plugin doesn’t properly clean (sanitize/escape) user input in the form_id attribute of the [callrail_form] shortcode.
Attackers with contributor permissions or above can use this to inject JavaScript into pages, which then runs in the browser of any visitor. That script could, for instance, steal cookies, keys, or even hijack the admin’s session.
Vulnerable Code Pattern
The critical flaw is in the way the plugin processes shortcode attributes provided by users. Here’s a simplified version of what’s happening:
// Imagine this in plugin: (pseudocode for clarity)
$form_id = $_GET['form_id'] ?? '';
echo '<div class="callrail-form" id="' . $form_id . '">';
If the $form_id isn’t properly escaped, an attacker could supply
form_id="foo" onmouseover="alert(1)"
So the generated HTML becomes
<div class="callrail-form" id="foo" onmouseover="alert(1)">
Or even using a <script> tag depending on context.
Publishes or saves the page.
4. Any user who visits the page (including admins) triggers the malicious script when they hover over the DIV.
What does this do?
- The onmouseover event executes JavaScript (alert('Hacked!')). Real attackers could do much worse, such as:
Mitigation
- Update the plugin to the latest version as soon as it’s available. Check CallRail's plugin page for updates.
Restrict Contributor and Editor roles if you don’t need them.
- Use a Web Application Firewall (like Wordfence) for added protection.
References
- Wordfence Advisory: CVE-2023-5051
- NVD Mitre Entry for CVE-2023-5051
- CallRail Phone Call Tracking Plugin WP Repo
Conclusion
CVE-2023-5051 is a textbook example of the dangers of unescaped user input. If you’re a WordPress site owner using the CallRail plugin, make sure you’ve updated to a secured version. Don’t take XSS lightly—even if only "trusted" contributors have access. All it takes is a single compromised account.
Stay safe and keep your plugins updated!
*Exclusive writeup for educational purposes only. Please use responsibly.*
Timeline
Published on: 10/27/2023 04:15:10 UTC
Last modified on: 11/07/2023 04:23:24 UTC