CVE-2018-20933 in cPanel
Summary
by MITRE
cPanel before 70.0.23 has Stored XSS via an WHM Edit DNS Zone action (SEC-410).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability CVE-2018-20933 represents a critical stored cross-site scripting flaw in cPanel software versions prior to 70.0.23, specifically within the WHM Edit DNS Zone functionality. This issue falls under the CWE-79 category of Cross-Site Scripting and demonstrates how web applications can fail to properly sanitize user input before storing and rendering it in web pages. The vulnerability exists in the administrative interface of cPanel, which is widely used by hosting providers and system administrators to manage web hosting accounts and DNS configurations.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing cross-site scripting payloads and submits it through the WHM Edit DNS Zone action. When the system stores this input without proper sanitization and subsequently displays it in the web interface, the malicious script executes within the context of other users' browsers who view the affected DNS zone records. This stored nature of the vulnerability means that the malicious payload persists in the system and affects multiple users who access the compromised interface, making it particularly dangerous in multi-tenant hosting environments where multiple customers share the same administrative interface.
The operational impact of CVE-2018-20933 extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation within the cPanel environment. Attackers can leverage this vulnerability to steal administrative sessions, modify DNS records to redirect traffic, or gain unauthorized access to customer accounts. The vulnerability is particularly concerning in hosting environments where cPanel serves as the primary administrative interface for managing thousands of customer accounts, as a single compromised zone could potentially affect numerous users.
Mitigation strategies for this vulnerability include immediate upgrade to cPanel version 70.0.23 or later, which contains the necessary patches to address the stored XSS flaw. Organizations should also implement additional security measures such as input validation and output encoding in web applications, regular security assessments of administrative interfaces, and monitoring for suspicious activities in DNS zone modifications. The ATT&CK framework categorizes this vulnerability under T1059.005 for Command and Scripting Interpreter and T1566.001 for Phishing, highlighting how such vulnerabilities can be exploited to establish persistent access and conduct social engineering attacks. Security teams should also consider implementing web application firewalls and regular penetration testing to identify similar stored XSS vulnerabilities in other components of their hosting infrastructure.