CVE-2017-18474 in cPanel
Summary
by MITRE
cPanel before 62.0.4 allows arbitrary file-read operations via Exim valiases (SEC-201).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2017-18474 represents a critical security flaw in cPanel versions prior to 62.0.4 that enables unauthorized file read operations through the Exim valiases functionality. This vulnerability specifically targets the email alias validation system within cPanel's email management infrastructure, creating a pathway for attackers to access sensitive files on the server that should normally be restricted. The issue stems from inadequate input validation and access control mechanisms within the Exim configuration processing component, allowing malicious actors to exploit a directory traversal vulnerability in the alias validation process.
The technical exploitation of this vulnerability occurs through the manipulation of Exim valiases parameters, which are used to define email forwarding rules and alias configurations within the cPanel environment. Attackers can craft specially formatted requests that bypass normal file access controls and retrieve arbitrary files from the server filesystem. This flaw operates at the application layer and can be leveraged to access configuration files, user data, and potentially sensitive system information that should remain protected. The vulnerability is particularly dangerous because it allows access to files outside the intended web root or email configuration directories, potentially exposing database credentials, private keys, or other confidential information stored on the server.
The operational impact of CVE-2017-18474 extends beyond simple data exposure, as it provides attackers with the capability to escalate privileges and potentially gain deeper system access. The vulnerability can be exploited by remote attackers without requiring authentication, making it particularly dangerous in multi-tenant hosting environments where multiple customers share the same infrastructure. Organizations using affected cPanel versions face significant risk of data breaches, compliance violations, and potential system compromise. The vulnerability aligns with CWE-22 (Directory Traversal) and CWE-200 (Information Disclosure) categories, representing a classic case of insufficient input sanitization leading to unauthorized access. According to ATT&CK framework, this vulnerability maps to T1083 (File and Directory Discovery) and T1213 (Data from Information Repositories) tactics, as it enables adversaries to discover and extract sensitive data from compromised systems.
Mitigation strategies for CVE-2017-18474 primarily focus on immediate remediation through cPanel version upgrades to 62.0.4 or later, which contain the necessary patches to address the Exim valiases validation flaw. Organizations should also implement network-level restrictions to limit access to cPanel administrative interfaces and consider additional monitoring for unusual file access patterns. Security teams should conduct comprehensive audits of email alias configurations and implement proper input validation controls within the Exim configuration processing pipeline. The vulnerability serves as a reminder of the critical importance of keeping hosting control panels updated and maintaining robust access controls for administrative interfaces. Organizations should also review their incident response procedures to ensure readiness for potential exploitation attempts and implement proper logging mechanisms to detect unauthorized file access attempts.