CVE-2018-20878 in cPanel
Summary
by MITRE
cPanel before 74.0.8 allows stored XSS in WHM "File and Directory Restoration" interface (SEC-441).
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Analysis
by VulDB Data Team • 07/17/2020
The vulnerability identified as CVE-2018-20878 represents a critical stored cross-site scripting flaw within the cPanel web hosting control panel software. This vulnerability specifically affects versions prior to 74.0.8 and resides within the WHM File and Directory Restoration interface, which is a core administrative component used by system administrators to manage file recovery operations. The issue stems from inadequate input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied data before rendering it within the web interface. This allows authenticated attackers with administrative privileges to inject malicious JavaScript code into the restoration process that persists and executes whenever the affected interface is accessed by other administrators.
The technical exploitation of this vulnerability occurs through the manipulation of input fields within the File and Directory Restoration functionality where users can specify file paths, directory names, or other metadata during the restoration process. When these inputs are stored in the system's database and subsequently rendered in the web interface without proper sanitization, the malicious code becomes persistent and executes in the context of other administrators' browsers. This stored XSS vector enables attackers to perform various malicious activities including session hijacking, credential theft, privilege escalation, and redirection to malicious sites. The vulnerability directly maps to CWE-79 which defines cross-site scripting flaws as weaknesses that occur when an application includes untrusted data in a new web page without proper validation or escaping, or without a security policy that prevents the browser from interpreting the data as executable code.
The operational impact of CVE-2018-20878 extends beyond simple data corruption or unauthorized access as it fundamentally compromises the integrity of the administrative interface that security teams rely upon for system management. Attackers can leverage this vulnerability to establish persistent backdoors within the control panel environment, monitor administrator activities, and potentially escalate privileges to gain full system control. The stored nature of the vulnerability means that even after the initial injection, the malicious payload continues to execute whenever any administrator accesses the affected restoration interface, creating a continuous threat vector. This vulnerability also aligns with ATT&CK technique T1059.007 which covers the use of scripting languages for execution, as the injected JavaScript code can be used to execute arbitrary commands on the server or redirect administrators to malicious sites.
Organizations utilizing cPanel versions prior to 74.0.8 face significant risk exposure from this vulnerability, particularly those with multiple administrators or those operating in environments where security is paramount. The remediation strategy involves immediate upgrade to cPanel version 74.0.8 or later, which includes proper input validation and output escaping mechanisms that prevent the storage and execution of malicious scripts. Additional mitigations include implementing strict input validation policies, monitoring administrative interface access logs for suspicious activities, and conducting regular security assessments of web applications. Security teams should also consider implementing web application firewalls and network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and proper input sanitization practices in web applications, particularly in administrative interfaces where elevated privileges can lead to complete system compromise.