CVE-2023-26541 in asMember Plugin
Summary
by MITRE • 06/16/2023
Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Alexander Suess asMember plugin <= 1.5.4 versions.
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Analysis
by VulDB Data Team • 07/14/2023
The CVE-2023-26541 vulnerability represents a critical stored cross-site scripting flaw within the asMember plugin for WordPress, specifically affecting versions up to and including 1.5.4. This vulnerability resides in the administrative authentication layer, requiring attackers to possess administrator-level privileges or higher to exploit the flaw. The issue stems from insufficient input validation and output encoding mechanisms within the plugin's codebase, allowing malicious actors with elevated access to inject persistent malicious scripts into the application's data storage. The vulnerability manifests when administrators interact with the plugin's administrative interface, where user-supplied data is not adequately sanitized before being stored in the database and subsequently rendered in subsequent page requests. This stored XSS condition creates a persistent threat vector that can affect all users who view the affected content, making it particularly dangerous in multi-user environments where administrators handle sensitive data. The vulnerability directly maps to CWE-79: Improper Neutralization of Input During Web Page Generation, which is a fundamental web application security weakness that enables attackers to inject malicious scripts into web pages viewed by other users. From an operational perspective, this vulnerability presents a significant risk to organizations relying on WordPress platforms with the asMember plugin, as it allows for potential session hijacking, credential theft, and unauthorized access to sensitive administrative data. The attack surface expands when considering that administrators often handle confidential information and may inadvertently interact with malicious payloads that have been stored in the system. The vulnerability also aligns with ATT&CK technique T1566.001: Phishing, as it enables attackers to craft malicious payloads that can be delivered to administrators through legitimate administrative interfaces, bypassing traditional security controls. The impact extends beyond simple script execution, potentially allowing for complete compromise of the affected WordPress installation through session manipulation and privilege escalation.
The technical exploitation of CVE-2023-26541 requires an attacker to first gain administrative access to the WordPress site, which then enables them to inject malicious JavaScript code through the plugin's administrative forms. Once injected, the malicious script is stored in the database and executed whenever affected pages are loaded by other users, including administrators themselves. The vulnerability's persistence stems from the lack of proper HTML escaping and context-aware output encoding mechanisms within the plugin's rendering functions. This allows attackers to inject script tags, event handlers, or other malicious payloads that can execute in the context of the victim's browser session. The vulnerability's severity is amplified by the fact that administrators typically have elevated privileges and access to sensitive data, making successful exploitation potentially catastrophic for organizational security. The stored nature of the vulnerability means that the malicious code remains active until manually removed from the database, creating a persistent threat that can be leveraged for extended periods. The flaw demonstrates poor input validation practices and inadequate sanitization of user-supplied data, which are core principles of secure web application development. Organizations should consider this vulnerability in the context of broader security frameworks, particularly those addressing privilege escalation and data integrity. The vulnerability's impact is further magnified in environments where multiple administrators interact with the same plugin interface, as each administrator could potentially become a vector for propagating the malicious payload to other users. This creates a network effect where a single compromised administrator account can lead to widespread compromise of the entire administrative ecosystem.
Mitigation strategies for CVE-2023-26541 should focus on immediate remediation through plugin version updates to versions that address the stored XSS vulnerability. Organizations must ensure that all instances of the asMember plugin are updated to the latest available version that contains proper input validation and output encoding fixes. Additionally, implementing proper access controls and privilege separation can help limit the potential impact of such vulnerabilities, ensuring that administrative privileges are granted only to trusted users with verified identities. Network monitoring and intrusion detection systems should be configured to detect unusual administrative activities that might indicate exploitation attempts. Security teams should also implement regular security audits of installed plugins and themes, particularly focusing on those with administrative interfaces that process user input. The vulnerability highlights the importance of proper output encoding and input validation at all levels of application development, aligning with industry standards such as OWASP Top Ten and NIST cybersecurity frameworks. Organizations should also consider implementing web application firewalls to detect and block malicious script injection attempts, while maintaining comprehensive backup and recovery procedures to quickly restore systems in case of successful exploitation. Regular security training for administrators can help prevent social engineering attacks that might lead to privilege escalation, and implementing multi-factor authentication for administrative accounts adds an additional layer of protection against unauthorized access. The remediation process should include thorough testing of updated plugin versions to ensure that security fixes do not introduce compatibility issues with existing site functionality.