CVE-2018-20919 in cPanel
Summary
by MITRE
cPanel before 70.0.23 allows stored XSS via a WHM Create Account action (SEC-373).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability CVE-2018-20919 represents a critical stored cross-site scripting flaw in cPanel versions prior to 70.0.23, specifically within the WHM Create Account functionality. This issue falls under the CWE-79 category of Cross-Site Scripting, where malicious input is permanently stored on the server and subsequently executed in users' browsers when they access affected pages. The vulnerability manifests in the Web Host Manager interface, which serves as the administrative control panel for cPanel hosting environments, making it a prime target for attackers seeking to compromise hosting infrastructure.
The technical exploitation occurs when an attacker crafts malicious input during the account creation process within WHM, which gets stored in the system's database without proper sanitization or encoding. When legitimate administrators or users view the created account information, the stored malicious script executes in their browser context, potentially leading to session hijacking, credential theft, or further exploitation of the compromised hosting environment. This stored XSS vulnerability is particularly dangerous because it can persist long after the initial injection, affecting anyone who views the affected account data regardless of their privileges or authentication status.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to gain unauthorized access to hosting environments and potentially compromise multiple customer accounts. Attackers can leverage this vulnerability to steal administrative credentials, inject malicious code into customer websites, or establish persistent backdoors within the hosting infrastructure. The vulnerability affects the core administrative functionality of cPanel, which serves millions of hosting accounts worldwide, making it a significant threat to hosting providers and their customers. This flaw directly aligns with ATT&CK technique T1059.006 for Command and Scripting Interpreter, as it allows for arbitrary code execution through browser-based attacks.
Organizations should immediately implement the patch released in cPanel version 70.0.23, which properly sanitizes user input during account creation processes. Additional mitigations include implementing strict input validation at multiple layers, deploying web application firewalls to detect and block malicious payloads, and conducting regular security audits of administrative interfaces. The vulnerability demonstrates the critical importance of proper output encoding and input validation in administrative web interfaces, as highlighted by CWE-79 requirements for preventing XSS attacks. Security teams should also consider implementing monitoring for unusual account creation patterns and conducting regular penetration testing to identify similar vulnerabilities in other administrative components of hosting infrastructure.