CVE-2018-20949 in cPanel
Summary
by MITRE
cPanel before 68.0.27 allows self XSS in WHM Apache Configuration Include Editor (SEC-385).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2018-20949 represents a self-cross-site scripting flaw within cPanel's WHM Apache Configuration Include Editor component. This issue affects cPanel versions prior to 68.0.27 and falls under the category of security misconfiguration that could potentially allow authenticated attackers with WHM access to execute malicious scripts within the context of the victim's browser. The vulnerability is particularly concerning because it operates within the administrative interface of a widely used web hosting control panel, potentially providing attackers with elevated privileges and access to sensitive server configurations.
The technical implementation of this self-XSS vulnerability stems from insufficient input validation and output encoding within the Apache Configuration Include Editor module. When administrators interact with this component to manage Apache configuration files, the application fails to properly sanitize user-supplied input before rendering it back to the browser. This oversight creates an opportunity for attackers to inject malicious JavaScript code that executes within the context of the WHM interface, leveraging the authenticated session of the administrator. The vulnerability specifically affects the include editor functionality where configuration directives are processed and displayed, making it particularly dangerous as it could be exploited to modify critical server configurations or exfiltrate sensitive data.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with potential access to the administrative interface of hosting environments. An attacker who successfully exploits this vulnerability could manipulate Apache configuration settings, potentially leading to service disruption, unauthorized access to hosted websites, or even complete compromise of the hosting environment. The self-XSS nature means that the malicious payload executes within the legitimate WHM session, making detection more challenging and allowing for persistent access to the administrative interface. This vulnerability aligns with CWE-79 Cross-site Scripting and follows patterns commonly associated with attack techniques described in the MITRE ATT&CK framework under the T1059.007 command and scripting interpreter category, where attackers leverage legitimate system tools to execute malicious code.
Organizations affected by this vulnerability should immediately upgrade to cPanel version 68.0.27 or later, which includes proper input validation and output encoding fixes for the Apache Configuration Include Editor. System administrators should also implement additional monitoring of WHM interface usage and consider implementing web application firewalls to detect and block suspicious script injection attempts. Security teams should conduct comprehensive audits of all administrative interfaces and ensure proper input sanitization practices are implemented across all web applications. The vulnerability demonstrates the critical importance of validating and sanitizing all user inputs within administrative interfaces, particularly those that directly impact system configurations, as highlighted in industry best practices for preventing XSS vulnerabilities. Organizations should also consider implementing multi-factor authentication for administrative accounts and regular security assessments of their hosting infrastructure to identify similar vulnerabilities in other components of their web hosting environments.