CVE-2017-18396 in cPanel
Summary
by MITRE
cPanel before 68.0.15 allows arbitrary file-read operations via Exim vdomainaliases (SEC-329).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability CVE-2017-18396 represents a critical arbitrary file read flaw in cPanel versions prior to 68.0.15, specifically affecting the Exim mail server configuration handling through vdomainaliases functionality. This issue stems from insufficient input validation and access control mechanisms within the cPanel administrative interface that processes virtual domain alias configurations. The vulnerability allows authenticated attackers with cPanel access to read arbitrary files on the system through improper handling of domain alias parameters in the Exim configuration process. The flaw exists in the way cPanel processes vdomainaliases, which are used to manage virtual domain configurations for email services, creating a path for unauthorized file access that bypasses normal file system permissions and security boundaries.
The technical exploitation of this vulnerability occurs through the manipulation of Exim vdomainaliases parameters within the cPanel interface, where the system fails to properly sanitize user-supplied input before processing it in the context of file system operations. This creates a path traversal condition that allows an attacker to specify arbitrary file paths that should normally be restricted. The vulnerability specifically affects the Exim mail server integration within cPanel, where domain alias configurations are processed and applied to the mail server configuration files. Attackers can leverage this flaw to read sensitive system files, configuration data, and potentially credentials stored in files that should remain protected from unauthorized access. The issue is categorized under CWE-22 as Path Traversal and aligns with ATT&CK technique T1005 for Data from Local System, demonstrating how improper input validation can lead to information disclosure.
The operational impact of CVE-2017-18396 is severe as it provides attackers with the ability to access sensitive data that could include system configuration files, email server credentials, and potentially user account information. Organizations running vulnerable cPanel versions face significant risk of data breaches, as this vulnerability enables unauthorized access to critical system information that could be used for further attacks or to compromise other system components. The vulnerability affects the integrity and confidentiality of the mail server configuration and can potentially expose sensitive data that may be used in privilege escalation attacks or to gain deeper access to the system. Security teams must consider this vulnerability as a potential entry point for attackers seeking to establish persistent access or to gather intelligence about the target environment. The flaw particularly impacts organizations that rely heavily on cPanel for web hosting management and email services, where the compromise of one account could potentially lead to broader system access.
Mitigation strategies for CVE-2017-18396 require immediate patching of cPanel installations to version 68.0.15 or later, which includes the necessary fixes to properly validate and sanitize input parameters used in vdomainaliases processing. Organizations should also implement network segmentation and access controls to limit exposure of cPanel interfaces to authorized users only, reducing the attack surface available to potential exploiters. Regular security audits should verify that all cPanel installations are updated to supported versions and that proper access controls are in place. System administrators should monitor for suspicious activity related to mail server configuration changes and implement logging of file access operations to detect potential exploitation attempts. The vulnerability highlights the importance of maintaining current security patches and proper input validation in web applications, particularly those handling sensitive system configurations and user data through administrative interfaces.