CVE-2018-20875 in cPanel
Summary
by MITRE
cPanel before 74.0.8 allows self XSS in the WHM Security Questions interface (SEC-433).
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Analysis
by VulDB Data Team • 07/17/2020
The vulnerability CVE-2018-20875 represents a self cross-site scripting flaw discovered in cPanel versions prior to 74.0.8 within the WHM Security Questions interface. This security weakness falls under the category of CWE-79 Cross-Site Scripting, specifically classified as self-XSS since the malicious payload is executed within the context of the authenticated user's session. The vulnerability exists in the security question management functionality that allows administrators to configure security questions for account recovery purposes. When an attacker can manipulate the input fields through crafted payloads, the malicious script executes in the context of the victim's browser session, potentially compromising the integrity of the security question system.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the WHM Security Questions interface. The affected component fails to properly escape or encode user-supplied data before rendering it back to the browser. This allows an attacker who has gained access to a privileged account to inject malicious JavaScript code into the security question fields. The vulnerability is particularly concerning because it operates within the administrative interface where sensitive security configurations are managed, potentially allowing attackers to escalate their privileges or compromise account recovery mechanisms. The flaw enables attackers to execute scripts that can steal session cookies, redirect users to malicious sites, or manipulate the security question data itself.
The operational impact of CVE-2018-20875 extends beyond simple script execution as it directly affects the security posture of cPanel installations. An attacker with access to the WHM interface can leverage this vulnerability to compromise the security question system, potentially gaining unauthorized access to accounts or manipulating recovery procedures. This weakness creates opportunities for privilege escalation attacks where malicious actors can modify security configurations to weaken account protection mechanisms. The self-XSS nature means that the attack requires a user to be authenticated and navigate to a maliciously crafted page, but the impact is significant because the attacker can manipulate the security question data that is critical for account recovery and authentication processes. The vulnerability aligns with ATT&CK technique T1078 Valid Accounts, as it could be used to maintain access or escalate privileges through compromised security question configurations.
Mitigation strategies for CVE-2018-20875 primarily focus on updating to cPanel version 74.0.8 or later, which contains the necessary patches to address the input validation and output encoding issues. Organizations should implement comprehensive input sanitization measures that properly escape or encode all user-supplied data before rendering it in the browser context. Security administrators should conduct regular audits of the WHM interface to ensure that security question configurations remain intact and free from malicious payloads. Additionally, implementing proper access controls and monitoring for unusual activity within the WHM interface can help detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation across all user-facing administrative interfaces and highlights the critical need for regular security updates to protect against known vulnerabilities. Organizations should also consider implementing web application firewalls and security monitoring solutions that can detect and prevent XSS attacks targeting administrative interfaces.