CVE-2017-18464 in cPanel
Summary
by MITRE
cPanel before 62.0.17 allows arbitrary file-overwrite operations via the WHM Zone Template editor (SEC-226).
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2017-18464 affects cPanel versions prior to 62.0.17 and represents a critical security flaw within the WHM Zone Template editor functionality. This issue enables malicious actors to perform arbitrary file overwrite operations, potentially compromising the integrity of system files and user data. The vulnerability specifically resides in the zone template editing component of the WHM interface, which is commonly used by system administrators to manage DNS zone files for hosting accounts. The flaw stems from inadequate input validation and sanitization mechanisms within the template editor, allowing attackers to manipulate file paths and overwrite critical system files. This vulnerability directly impacts the principle of least privilege and file system integrity, as it bypasses normal access controls and file permission checks that should normally prevent unauthorized file modifications.
The technical exploitation of this vulnerability occurs through the manipulation of parameters within the WHM Zone Template editor interface. Attackers can craft malicious requests that target specific file paths, potentially overwriting configuration files, binaries, or other critical system components. The flaw operates at the application level and leverages the trust placed in legitimate administrative functions within the cPanel environment. This vulnerability falls under CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The exploitation process typically involves sending specially crafted HTTP requests to the WHM interface that contain malicious path references, allowing the attacker to write content to arbitrary locations on the filesystem. The vulnerability demonstrates a classic lack of proper input validation and output encoding that enables attackers to manipulate the application's intended behavior and gain unauthorized access to system resources.
The operational impact of CVE-2017-18464 extends beyond simple file overwrite capabilities and can lead to complete system compromise when exploited effectively. An attacker who successfully exploits this vulnerability can potentially overwrite critical system files such as configuration files, binary executables, or even system libraries, leading to service disruption, privilege escalation, or complete system takeover. The vulnerability affects organizations that rely on cPanel for hosting management, particularly those with multiple hosting accounts or complex DNS configurations. The attack surface is significant as the WHM interface is typically accessible to system administrators and potentially to other authorized users, making this vulnerability particularly dangerous in multi-user environments. Organizations may experience data loss, service interruptions, and potential regulatory compliance violations when this vulnerability is exploited. The impact is further exacerbated by the fact that this vulnerability allows for arbitrary file overwrites, meaning attackers can potentially replace legitimate files with malicious versions, creating persistent backdoors or enabling further attack vectors.
Mitigation strategies for CVE-2017-18464 primarily focus on immediate remediation through software updates and implementation of additional security controls. The most effective immediate solution is to upgrade cPanel to version 62.0.17 or later, which includes patches specifically addressing the file overwrite vulnerability in the WHM Zone Template editor. Organizations should also implement network segmentation and access control measures to limit exposure of the WHM interface to trusted networks only. Additional mitigations include implementing web application firewalls to monitor and filter suspicious requests targeting the WHM interface, enforcing strict input validation on all user-supplied data, and conducting regular security audits of the cPanel configuration. System administrators should also implement monitoring solutions that can detect unusual file modification patterns or unauthorized access attempts to critical system files. The vulnerability demonstrates the importance of secure coding practices and input validation, aligning with ATT&CK technique T1059.001 for command and scripting interpreter and T1566.001 for credential access through exploitation of vulnerabilities. Organizations should also consider implementing principle of least privilege controls, ensuring that only necessary users have access to the WHM interface and that administrative privileges are granted based on strict need-to-know requirements. Regular security assessments and penetration testing should be conducted to identify and remediate similar vulnerabilities in other system components.