CVE-2021-24344 in Easy Preloader Plugin
Summary
by MITRE • 06/07/2021
The Easy Preloader WordPress plugin through 1.0.0 does not sanitise its setting fields, leading to authenticated (admin+) Stored Cross-Site scripting issues
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Analysis
by VulDB Data Team • 06/10/2021
The CVE-2021-24344 vulnerability affects the Easy Preloader WordPress plugin version 1.0.0 and earlier, representing a critical security flaw that enables authenticated attackers with administrator privileges to execute stored cross-site scripting attacks. This vulnerability resides within the plugin's handling of user input through its settings fields, where insufficient sanitization allows malicious code to be persisted and subsequently executed when other users access the affected administrative interfaces. The flaw demonstrates a classic stored XSS vulnerability pattern where attacker-controlled data is stored in the application's database and later rendered to unsuspecting users without proper output encoding or validation.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user-supplied input before storing it in the WordPress database. When administrators configure the plugin settings, the input values are directly saved without appropriate sanitization measures, creating a persistent vector for malicious code injection. This weakness aligns with CWE-79, which categorizes cross-site scripting vulnerabilities as a result of insufficient input validation and output encoding. The vulnerability specifically targets the plugin's administrative interface where settings are managed, making it particularly dangerous as it requires only administrative access to exploit rather than more complex attack vectors.
From an operational perspective, this vulnerability presents significant risks to WordPress installations using the affected plugin, as it allows attackers to execute malicious scripts in the context of the victim's browser session. The stored nature of the XSS means that the malicious code remains persistent and can affect multiple users who access the compromised administrative interfaces. Attackers could leverage this vulnerability to steal administrator session cookies, modify plugin configurations, or redirect users to malicious domains. The impact extends beyond simple data theft, as administrators with elevated privileges could be fully compromised, potentially leading to complete system takeover. This vulnerability directly maps to ATT&CK technique T1059.001 for command and control through script injection, and T1547.001 for privilege escalation through administrative access exploitation.
Mitigation strategies for CVE-2021-24344 should prioritize immediate plugin updates to versions that address the sanitization issues, as the vendor has likely released patches to resolve the vulnerability. Organizations should also implement additional security measures including regular security audits of installed plugins, monitoring for unauthorized administrative changes, and implementing web application firewalls to detect and block suspicious input patterns. The remediation process should include thorough testing of updated plugin versions to ensure compatibility with existing site configurations, while administrators should review and validate all plugin settings to identify any previously injected malicious code. Security teams should also consider implementing input validation rules at the application level and establishing monitoring procedures for detecting unauthorized modifications to plugin settings, as the vulnerability specifically targets administrative interfaces where legitimate users might not expect such security risks to exist.