CVE-2023-0899 in Steveas WP Live Chat Shoutbox Plugin
Summary
by MITRE • 04/24/2023
The Steveas WP Live Chat Shoutbox WordPress plugin through 1.4.2 does not sanitise and escape a parameter before outputting it back in the Shoutbox, leading to Stored Cross-Site Scripting which could be used against high privilege users such as admins.
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Analysis
by VulDB Data Team • 05/18/2023
The CVE-2023-0899 vulnerability affects the Steveas WP Live Chat Shoutbox WordPress plugin version 1.4.2 and earlier, representing a critical stored cross-site scripting flaw that poses significant risks to WordPress administrators and high-privilege users. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's codebase, creating a persistent security weakness that allows attackers to inject malicious scripts into the shoutbox functionality. The flaw specifically occurs when user-supplied parameters are not properly sanitized before being rendered back to users, enabling attackers to execute arbitrary JavaScript code in the context of the victim's browser. Given that the vulnerability targets the shoutbox component where administrators frequently interact, it presents an ideal vector for compromising high-privilege accounts through persistent XSS attacks.
The technical implementation of this vulnerability aligns with CWE-79, which identifies cross-site scripting as a critical weakness in web applications. The flaw operates by accepting user input through the shoutbox parameter without proper validation or sanitization, allowing malicious payloads to be stored within the plugin's data storage and subsequently executed whenever the affected page is loaded. This stored nature of the vulnerability means that once exploited, the malicious script persists and will execute automatically for any user who views the shoutbox content, including administrators who may inadvertently trigger the payload. The vulnerability's impact is amplified because the shoutbox functionality is often visible to multiple users simultaneously, potentially allowing attackers to compromise multiple accounts during a single attack window. The lack of proper escaping mechanisms ensures that any HTML or JavaScript content entered by attackers is rendered directly in the browser without appropriate security measures to prevent execution.
The operational impact of this vulnerability extends beyond simple script execution, as it creates opportunities for attackers to escalate privileges, steal session cookies, perform unauthorized actions within the WordPress admin interface, and potentially gain complete control over affected websites. High-privilege users such as administrators are particularly vulnerable because their sessions are typically more valuable and the XSS attack can be used to capture their authentication tokens or redirect them to malicious sites. Attackers can leverage this vulnerability to perform session hijacking, modify website content, create new administrator accounts, or exfiltrate sensitive data from the WordPress installation. The persistence of stored XSS makes this vulnerability particularly dangerous as it can remain active for extended periods without requiring repeated exploitation attempts, and the attack surface includes not only the shoutbox but any other components that may display the maliciously stored content.
Mitigation strategies for CVE-2023-0899 should prioritize immediate plugin updates to versions that address the sanitization and escaping issues, as recommended by the plugin developers and WordPress security teams. Organizations should implement comprehensive input validation and output escaping measures at the application level, ensuring that all user-supplied data is properly sanitized before being stored or rendered back to users. Security monitoring should include regular scanning for stored XSS vulnerabilities in custom plugins and themes, with particular attention to functionality that handles user-generated content. The implementation of Content Security Policy headers can provide additional defense-in-depth measures to prevent execution of unauthorized scripts, while regular security audits of WordPress installations should include assessment of third-party plugin security practices. According to ATT&CK framework category T1531, this vulnerability represents a technique for privilege escalation through client-side attacks, making it essential for security teams to monitor and remediate such issues proactively. Network-level monitoring should also be implemented to detect suspicious payloads being injected into the shoutbox functionality, and access controls should be reviewed to ensure that only authorized users can post content to potentially vulnerable components of the website.