CVE-2016-10806 in cPanel
Summary
by MITRE
cPanel before 57.9999.54 allows self XSS on the Paper Lantern Landing Page (SEC-110).
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Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2016-10806 represents a critical self-cross-site scripting flaw within cPanel software versions prior to 57.9999.54. This issue specifically affects the Paper Lantern theme's landing page, which serves as the primary interface for users accessing their hosting control panel. The vulnerability arises from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it within the web interface. Attackers can exploit this weakness by crafting malicious payloads that, when executed within the context of a victim's browser session, can persist and affect other users who visit the compromised landing page.
The technical exploitation of this self-XSS vulnerability occurs through the manipulation of parameters or input fields within the Paper Lantern theme's landing page functionality. When user-provided data is not adequately sanitized before being displayed back to the user, malicious scripts can be injected and executed in the victim's browser context. This creates a persistent threat where the malicious payload remains stored within the application's interface and executes whenever the affected page is loaded. The vulnerability operates under CWE-79 which classifies it as a Cross-Site Scripting weakness, specifically manifesting as a self-XSS variant where the attacker can execute malicious code against themselves to establish a persistent malicious context. The attack follows patterns consistent with ATT&CK technique T1059.001 for command and scripting interpreter, where the malicious code execution occurs through web-based interfaces.
The operational impact of this vulnerability extends beyond simple script injection as it can enable attackers to establish persistent access to user sessions, potentially leading to privilege escalation or session hijacking. Since cPanel serves as a critical administrative interface for hosting environments, an attacker who successfully exploits this vulnerability can gain unauthorized access to sensitive user data, modify account configurations, or establish backdoors within the hosting infrastructure. The self-XSS nature means that the malicious payload can remain active even after the initial attack vector is closed, creating a persistent threat that can affect multiple users over time. This vulnerability is particularly dangerous in shared hosting environments where multiple users share the same infrastructure, as it can provide attackers with access to various user accounts and their associated data.
Mitigation strategies for CVE-2016-10806 require immediate patching of affected cPanel installations to version 57.9999.54 or later, which includes proper input validation and output encoding fixes. Organizations should implement comprehensive web application firewall rules to detect and block suspicious script injection attempts, particularly targeting the Paper Lantern theme's landing page endpoints. Additional protective measures include implementing strict content security policies to prevent script execution, conducting regular security audits of web interfaces, and establishing user access monitoring to detect anomalous behavior patterns. Security teams should also consider implementing multi-factor authentication for administrative accounts and regularly reviewing user session management configurations to minimize the potential impact of successful exploitation attempts. The vulnerability highlights the importance of proper input sanitization and output encoding practices in web applications, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity guidelines.