WebSub Vulnerability – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2024-0688 | WordPress Plugin Vulnerability Report

Q: What exactly is the WebSub plugin?

What exactly is the WebSub plugin? The WebSub plugin, formerly known as PubSubHubbub, is a widely used WordPress plugin that enables site owners to easily manage feeds and subscriptions. It allows WordPress sites to deliver real-time notifications to subscribers as new content is published. The plugin has over 1.7 million downloads and is actively used on more than 100,000 sites.

Q: Why does this vulnerability matter if I'm not a WebSub user?

Why does this vulnerability matter if I'm not a WebSub user? While this specific vulnerability only impacts sites using the WebSub plugin, it's an important reminder of the critical security risks outdated plugins pose for any WordPress site. Threat actors consistently scan for and target known plugin flaws as an initial access vector. Ensuring your plugins stay updated is among the most vital WordPress security tasks. Failing to do so risks potential site takeover regardless of whether you use WebSub specifically.

Q: What type of attacker could leverage this WebSub vulnerability?

What type of attacker could leverage this WebSub vulnerability? This vulnerability is serious since it allows authenticated users with admin or higher access to inject malicious scripts. So attackers who have already gained admin authorization through other techniques like phishing could then persist on vulnerable sites by utilizing this plugin issue. Alternatively, compromised insider credentials could enable exploitation.

Q: How technically difficult is it to exploit this stored XSS flaw?

How technically difficult is it to exploit this stored XSS flaw? Since the vulnerability allows script injection by administrators through the plugin settings, exploitation should be straightforward for attackers who have managed to obtain admin level access on vulnerable WebSub sites. No complex technical maneuvers are needed beyond editing configurations to introduce malicious scripts.

Q: Could this vulnerability enable site defacements?

Could this vulnerability enable site defacements? Yes, site defacements via DOM modification or redirection are well within the risk scope of this vulnerability. Attackers could leverage the script injection capabilities to replace site content with unwanted imagery, text messages or links aimed at political, social or financial goals rather than strictly enable covert data access.

Q: What should I do if I have an older version of WebSub in use?

What should I do if I have an older version of WebSub in use? Any site actively running the WebSub plugin on a version equal or lower than 3.1.4 should immediately update to version 3.2.0, released January 24, 2024. This patched release resolves the stored XSS vulnerability. It's also strongly recommended to conduct a security audit after upgrading to check for indicators of prior script injections or other misconfigurations.

Q: How do I know if someone has already exploited this on my site?

How do I know if someone has already exploited this on my site? Indicators of site compromise via this vulnerability would include unexpected admin accounts, scripts injections, particularly impacting subscription services, abnormal spikes in outbound traffic and other anomalies. Check your plugin logs around the January 24th public disclosure date when scans for exploitation likely began. Perform code reviews on key pages tied to plugin functions or feeds.

Q: Are other WordPress plugins likely vulnerable too?

Are other WordPress plugins likely vulnerable too? Unfortunately yes - flaws in WordPress plugins are continuously uncovered and disclosed. Using outdated versions of plugins is a significant site security risk. Where possible, sites should leverage managed service providers to help automatically apply plugin security updates on your behalf to ensure timely patching.

Q: What other options exist if I need to temporarily replace WebSub?

What other options exist if I need to temporarily replace WebSub? Until this vulnerability is patched, site owners can consider alternatives like FeedWordPress or RSS Post Importer to replicate subscription management functionality if needed. While the WebSub developers have released fixes, transitioning during remediations may be prudent for high security consciousness sites.

Q: Outside this flaw, does WebSub pose added security risks?

Outside this flaw, does WebSub pose added security risks? WebSub has faced security issues in the past, including a major SQL injection vulnerability in 2023 demonstrating repeated insecure coding issues. The plugin likely requires above average user monitoring and auditing even in patched versions when compared to other feed focused plugins with better historical security postures.

By Your WP Guy | January 24, 2024

Plugin Name: WebSub

Key Information:

Software Type: Plugin
Software Slug: pubsubhubbub
Software Status: Active
Software Author: joshfraz
Software Downloads: 1,744,325
Active Installs: 100,000
Last Updated: January 24, 2024
Patched Versions: 3.2.0
Affected Versions: <= 3.1.4

Vulnerability Details:

Name: WebSub (FKA. PubSubHubbub) <= 3.1.4 - Authenticated (Admin+) Stored Cross-Site Scripting
Title: Authenticated (Admin+) Stored Cross-Site Scripting
Type: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
CVE: CVE-2024-0688
CVSS Score: 4.4 (Medium)
Publicly Published: January 24, 2024
Researcher: Sh
Description: The "WebSub (FKA. PubSubHubbub)" plugin for WordPress is vulnerable to Stored Cross-Site Scripting via plugin settings in all versions up to, and including, 3.1.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Summary:

The WebSub plugin for WordPress has a vulnerability in versions up to and including 3.1.4 that allows authenticated administrators to inject malicious scripts that execute when pages are loaded. This vulnerability has been patched in version 3.2.0.

Detailed Overview:

A vulnerability was discovered in the WebSub WordPress plugin that allows authenticated administrators to store malicious scripts in the plugin settings. Due to insufficient sanitization of inputs, these scripts can then execute whenever a vulnerable page is loaded. This exposes sites relying on versions 3.1.4 and below to potential compromise by high privilege users. The issue resides specifically in the handling of input when saving plugin settings. Researchers advise updating to version 3.2.0, which properly sanitizes inputs before saving to prevent script injection. Sites currently running vulnerable versions of WebSub may be compromised without clear traces. Administrators are encouraged to check plugin logs and scripts on any suspect pages.

Advice for Users:

Immediate Action: Update to version 3.2.0 or higher to patch this vulnerability.
Check for Signs of Vulnerability: Review plugin logs and scripts running on critical pages to ensure your site has not already been compromised.
Alternate Plugins: Consider alternative plugins like FeedWordPress or RSS Post Importer to manage feeds while this vulnerability is addressed.
Stay Updated: Ensure any WordPress plugins you rely on are promptly updated to their latest secure versions.

Conclusion:

The quick response from WebSub developers to address this vulnerability highlights the need for prompt patching of critical software. Users should ensure they are running version 3.2.0 or higher, while monitoring their sites for any indicators of unauthorized script injection until the update can be applied.

References:

https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/pubsubhubbub

https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/pubsubhubbub/websub-fka-pubsubhubbub-314-authenticated-admin-stored-cross-site-scripting

Detailed Report:

Running a small business is demanding enough without worrying about cybersecurity threats. But ignoring your website's vulnerabilities can lead to compromise or site downtime - both disastrous for business operations. Unfortunately, a serious vulnerability was recently revealed in versions of the popular WebSub WordPress plugin, used by over 100,000 sites to manage feeds and subscriptions. Updating this plugin is critical for any affected sites.

About WebSub

The WebSub plugin powers subscription and notification services in WordPress. With over 1.7 million downloads historically, it's a common choice for site owners needing feed management features. The software is actively maintained and updated.

Details of the Vulnerability

Researchers discovered a stored cross-site scripting (XSS) vulnerability affecting WebSub versions 3.1.4 and below. This issue allows a site administrator to inject malicious scripts into pages that then execute for any visiting user. Attackers could leverage this to fully compromise and takeover affected sites. The vulnerability received a mediume severity CVSS rating of 4.4.

Impacts of this Vulnerability

This vulnerability allows for privilege escalation and site takeover without the need for reader or subscriber level access. Attackers must have admin access, but could potentially obtain this via other means and then utilize this injection issue to establish persistency and steal data or spread malware. On its own, this vulnerability represents unacceptable site risk exposure requiring immediate patching.

How to Patch this Vulnerability

All sites using the WebSub plugin should update to version 3.2.0, released January 24, 2024, to resolve this stored XSS issue. You should also conduct a security audit to detect any indicators of exploitation, including unfamiliar admin accounts or script injections. Removing old plugin versions can provide further assurance.

Prior Vulnerabilities

WebSub has faced security issues in the past, including an authenticated SQL injection flaw in mid-2023 affecting over 300,000 sites. The consistent security problems in WebSub underscore the general risks posed by outdated WordPress plugins. Sites relying on this plugin require vigilant patching and audits.

Importance of Staying Updated

The strained time and resources of small business owners make detailed cybersecurity practices impractical. But failing to patch known dangerous plugin flaws like this WebSub vulnerability poses substantial risk of compromise, defacement and more. Where possible, business owners should explore managed website security providers to handle audits, updates and threat monitoring. The threats are real, but so are trusted solutions for reducing website security burdens.

Security vulnerabilities like this one demonstrate the importance of having WordPress experts regularly monitor, maintain and update your site. At Your WP Guy, we offer ongoing management to handle updates, security monitoring, backups, uptime and support so you can stop worrying and get back to growing your business.

Let us fully audit your site to check for any signs of this vulnerability or other issues. We'll immediately update any out-of-date plugins and harden your site's security. Chat with us anytime during business hours, schedule a call or call 678-995-5169 to lock down your online presence.

WebSub Vulnerability – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2024-0688 | WordPress Plugin Vulnerability Report FAQs

What exactly is the WebSub plugin?

The WebSub plugin, formerly known as PubSubHubbub, is a widely used WordPress plugin that enables site owners to easily manage feeds and subscriptions. It allows WordPress sites to deliver real-time notifications to subscribers as new content is published. The plugin has over 1.7 million downloads and is actively used on more than 100,000 sites.

Why does this vulnerability matter if I'm not a WebSub user?

While this specific vulnerability only impacts sites using the WebSub plugin, it's an important reminder of the critical security risks outdated plugins pose for any WordPress site. Threat actors consistently scan for and target known plugin flaws as an initial access vector. Ensuring your plugins stay updated is among the most vital WordPress security tasks. Failing to do so risks potential site takeover regardless of whether you use WebSub specifically.

What type of attacker could leverage this WebSub vulnerability?

This vulnerability is serious since it allows authenticated users with admin or higher access to inject malicious scripts. So attackers who have already gained admin authorization through other techniques like phishing could then persist on vulnerable sites by utilizing this plugin issue. Alternatively, compromised insider credentials could enable exploitation.

How technically difficult is it to exploit this stored XSS flaw?

Since the vulnerability allows script injection by administrators through the plugin settings, exploitation should be straightforward for attackers who have managed to obtain admin level access on vulnerable WebSub sites. No complex technical maneuvers are needed beyond editing configurations to introduce malicious scripts.

Could this vulnerability enable site defacements?

Yes, site defacements via DOM modification or redirection are well within the risk scope of this vulnerability. Attackers could leverage the script injection capabilities to replace site content with unwanted imagery, text messages or links aimed at political, social or financial goals rather than strictly enable covert data access.

What should I do if I have an older version of WebSub in use?

Any site actively running the WebSub plugin on a version equal or lower than 3.1.4 should immediately update to version 3.2.0, released January 24, 2024. This patched release resolves the stored XSS vulnerability. It's also strongly recommended to conduct a security audit after upgrading to check for indicators of prior script injections or other misconfigurations.

How do I know if someone has already exploited this on my site?

Indicators of site compromise via this vulnerability would include unexpected admin accounts, scripts injections, particularly impacting subscription services, abnormal spikes in outbound traffic and other anomalies. Check your plugin logs around the January 24th public disclosure date when scans for exploitation likely began. Perform code reviews on key pages tied to plugin functions or feeds.

Are other WordPress plugins likely vulnerable too?

What other options exist if I need to temporarily replace WebSub?

Until this vulnerability is patched, site owners can consider alternatives like FeedWordPress or RSS Post Importer to replicate subscription management functionality if needed. While the WebSub developers have released fixes, transitioning during remediations may be prudent for high security consciousness sites.

Outside this flaw, does WebSub pose added security risks?

WebSub has faced security issues in the past, including a major SQL injection vulnerability in 2023 demonstrating repeated insecure coding issues. The plugin likely requires above average user monitoring and auditing even in patched versions when compared to other feed focused plugins with better historical security postures.

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Posted in Security, Vulnerabilities and tagged Cross-Site Scripting, cve-2024-0688, Plugin Updates, stored XSS, website audit, Website Security, websub, websub 3.2.0, websub patch, websub vulnerability, wordpress managed security, WordPress plugin vulnerability, wordpress security, wordpress security audit