CVE-2020-35582 in Envira Gallery Lite
Summary
by MITRE • 01/15/2021
A stored cross-site scripting (XSS) issue in Envira Gallery Lite before 1.8.3.3 allows remote attackers to inject arbitrary JavaScript/HTML code via a POST /wp-admin/post.php request with the post_title parameter.
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Analysis
by VulDB Data Team • 02/14/2021
The vulnerability identified as CVE-2020-35582 represents a critical stored cross-site scripting flaw within the Envira Gallery Lite WordPress plugin version 1.8.3.2 and earlier. This issue resides in the plugin's handling of user input during post creation or editing processes, specifically when processing the post_title parameter through POST requests to the wp-admin/post.php endpoint. The flaw enables remote attackers to inject malicious JavaScript or HTML code that persists in the application's database and executes whenever affected pages are viewed by other users. This stored nature of the vulnerability makes it particularly dangerous as the malicious code becomes part of the legitimate content and can affect multiple users without requiring them to interact with the malicious payload directly. The vulnerability falls under CWE-79 which defines cross-site scripting as a weakness where untrusted data is sent to a web browser without proper validation or sanitization, allowing attackers to execute scripts in the context of the victim's browser session. The attack vector specifically targets the WordPress administrative interface where users with appropriate privileges create or modify posts, making it a significant concern for content management systems where administrators frequently interact with the plugin's functionality.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious payload and submits it through the post_title parameter in a POST request to the wp-admin/post.php endpoint. When the plugin processes this input without proper sanitization, the malicious code gets stored in the WordPress database as part of the post title. Subsequently, when other users view the affected posts or administrative interfaces, the stored script executes in their browsers, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The vulnerability demonstrates a classic case of inadequate input validation and output escaping in web applications, where user-supplied data is not properly filtered before being stored and subsequently rendered to end users. This flaw aligns with ATT&CK technique T1566.001 which describes social engineering through the use of malicious content, and more specifically relates to the exploitation of web application vulnerabilities to achieve persistent access to target systems. The impact is amplified by the fact that WordPress administrators typically have elevated privileges, meaning successful exploitation could provide attackers with administrative access to entire websites, potentially leading to full system compromise.
The operational impact of CVE-2020-35582 extends beyond simple script execution as it provides attackers with a persistent foothold within WordPress environments. When administrators or other users view affected posts, the malicious scripts can perform various harmful actions including stealing cookies, redirecting traffic, defacing websites, or even installing additional malware. The vulnerability affects the integrity of the WordPress content management system by allowing unauthorized modifications to the application's behavior through stored malicious code. Organizations using the affected plugin version face significant risks including data breaches, website defacement, and potential compromise of user credentials. The stored nature of the vulnerability means that the malicious code remains active until the plugin is updated or the affected content is manually removed, creating a long-term security risk. Security teams must consider the implications for their incident response procedures, as this vulnerability could be exploited to establish persistent backdoors or exfiltrate sensitive information from compromised WordPress installations. The vulnerability also highlights the importance of keeping WordPress plugins updated, as the issue was resolved in version 1.8.3.3 of the Envira Gallery Lite plugin, demonstrating how timely patch management serves as a critical defense mechanism against such attacks. Organizations should implement comprehensive monitoring of their WordPress installations to detect unauthorized modifications and ensure that all plugins and themes remain current with security patches to prevent exploitation of similar vulnerabilities.