CVE-2021-24771 in Inspirational Quote Rotator Plugin
Summary
by MITRE • 12/13/2021
The Inspirational Quote Rotator WordPress plugin through 1.0.0 does not sanitize and escape some of its quote fields when adding/editing a quote as admin, leading to Stored Cross-Site scripting issues when the quote is output in the "Quotes list" even when the unfiltered_html capability is disallowed
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Analysis
by VulDB Data Team • 12/16/2021
The Inspirational Quote Rotator WordPress plugin version 1.0.0 contains a critical stored cross-site scripting vulnerability that arises from inadequate input sanitization and output escaping mechanisms within its administrative interface. This vulnerability specifically affects the plugin's handling of quote fields during creation and modification processes, where user-provided content fails to undergo proper sanitization before being stored in the database. The flaw manifests when administrators add or edit quotes through the WordPress admin panel, creating a persistent security risk that affects all users who view the quotes list display.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user inputs that are subsequently rendered in the frontend quotes list display. When quote data is stored without adequate sanitization, malicious actors can inject malicious scripts that execute in the context of other users' browsers when they view the quotes list. This represents a classic stored XSS attack vector where the malicious payload is permanently stored on the server and executed whenever the vulnerable page is accessed. The vulnerability is particularly concerning because it occurs even when the WordPress environment has properly restricted the unfiltered_html capability, which should normally prevent such attacks.
The operational impact of this vulnerability extends beyond simple script execution as it allows attackers to potentially steal user sessions, deface the website, redirect users to malicious sites, or perform actions on behalf of authenticated users. The stored nature of the vulnerability means that once an attacker successfully injects malicious content, the payload persists and affects all users who view the quotes list, making it a significant risk for websites relying on this plugin. This vulnerability undermines the security model of WordPress by allowing unprivileged attackers to exploit administrative interfaces and potentially escalate their privileges or compromise user data through session hijacking.
Security professionals should note that this vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and represents a failure in the principle of least privilege as the plugin does not properly validate or escape user inputs before storage. The ATT&CK framework categorizes this as a web application vulnerability that enables initial access and privilege escalation through client-side exploitation. Organizations using this plugin should immediately implement mitigations including input validation, output escaping, and proper content sanitization before any updates are available. The vulnerability demonstrates the critical importance of proper input validation in web applications and the potential for seemingly minor security oversights to create significant risks in content management systems.