CVE-2017-18400 in cPanel
Summary
by MITRE
cPanel before 68.0.15 allows local root code execution via cpdavd (SEC-333).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2017-18400 represents a critical local privilege escalation flaw in cPanel versions prior to 68.0.15. This issue specifically affects the cpdavd service which is responsible for handling dav (WebDAV) operations within the cPanel environment. The vulnerability stems from improper privilege handling within the cpdavd daemon process that runs with elevated privileges. When exploited, this flaw allows a local attacker to execute arbitrary code with root privileges, effectively compromising the entire system. The vulnerability was categorized as a local privilege escalation issue with a severity level that reflects its potential for complete system compromise.
The technical root cause of this vulnerability lies in the cpdavd service's failure to properly validate or sanitize input parameters during WebDAV operations. The service operates with root privileges to perform necessary system functions but does not adequately restrict the execution context of incoming requests. Attackers can manipulate specific parameters passed to the cpdavd daemon to trigger code execution within the privileged context. This flaw aligns with CWE-20, which describes improper input validation, and CWE-78, which addresses OS command injection vulnerabilities. The vulnerability operates through a command injection vector where untrusted input is directly incorporated into system commands without proper sanitization or escaping mechanisms.
The operational impact of this vulnerability is severe and far-reaching within cPanel environments. System administrators who rely on cPanel for hosting management face significant risk when running affected versions, as any local user with minimal access can escalate privileges to root level. This creates a pathway for attackers to gain complete control over hosting servers, potentially leading to data breaches, service disruption, and unauthorized access to multiple customer accounts. The vulnerability affects systems where cPanel is installed and running the vulnerable cpdavd service, making it particularly dangerous in shared hosting environments where multiple users may have access to the system. According to ATT&CK framework, this vulnerability maps to T1068 (Local Privilege Escalation) and T1548.001 (Abuse Elevation Control Mechanism), demonstrating how the flaw can be leveraged to bypass security controls and achieve elevated system access.
Mitigation strategies for CVE-2017-18400 primarily involve immediate patching of the cPanel software to version 68.0.15 or later, which contains the necessary fixes to address the privilege escalation vulnerability. System administrators should also implement network segmentation and access controls to limit local user access to systems running cPanel. Additional defensive measures include monitoring for suspicious cpdavd process behavior, implementing intrusion detection systems to identify potential exploitation attempts, and conducting regular security audits of hosting environments. Organizations should also consider disabling the cpdavd service if WebDAV functionality is not required, as this eliminates the attack surface entirely. The vulnerability highlights the importance of keeping hosting software updated and maintaining proper access controls to prevent local privilege escalation attacks that could lead to complete system compromise.