CVE-2017-18447 in cPanel
Summary
by MITRE
cPanel before 64.0.21 allows demo accounts to execute code via the ClamScanner_getsocket API (SEC-251).
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Analysis
by VulDB Data Team • 07/19/2020
The vulnerability CVE-2017-18447 represents a critical security flaw in cPanel software versions prior to 64.0.21 that enables demo accounts to achieve remote code execution through the ClamScanner_getsocket API endpoint. This vulnerability falls under the category of insufficient authorization checks and privilege escalation, as demonstrated by the ability of unauthenticated demo users to leverage a legitimate API function for malicious purposes. The flaw specifically exploits the lack of proper access controls within the ClamScanner_getsocket API, which was designed to provide socket information for ClamAV antivirus scanning operations but was not properly secured against unauthorized access.
The technical implementation of this vulnerability stems from the improper validation of user permissions within the cPanel API framework. When demo accounts attempt to access the ClamScanner_getsocket endpoint, the system fails to verify whether the requesting user possesses the necessary privileges to execute the underlying commands. This oversight creates a path for privilege escalation where demo accounts can bypass normal security boundaries and execute arbitrary code on the server. The vulnerability is particularly concerning because demo accounts are typically intended to provide limited functionality for demonstration purposes only, yet this flaw allows them to perform actions that should be restricted to administrative users. This misconfiguration aligns with CWE-285, which addresses insufficient authorization issues in software systems, and demonstrates how weak access control mechanisms can lead to severe security implications.
The operational impact of CVE-2017-18447 extends beyond simple privilege escalation to encompass potential full system compromise and data breach scenarios. An attacker exploiting this vulnerability could execute malicious code with the privileges of the web server process, potentially leading to unauthorized access to sensitive customer data, server file manipulation, and further network reconnaissance. The vulnerability also poses significant risk to hosting providers who rely on cPanel for their infrastructure, as compromised demo accounts could serve as entry points for broader attacks against their entire hosting environment. This type of vulnerability is particularly dangerous in multi-tenant hosting environments where multiple customers share the same physical infrastructure, as it could enable cross-contamination between different customer accounts. The attack vector is relatively straightforward since demo accounts are often enabled by default and may not be properly monitored or restricted, making this vulnerability exploitable in environments with minimal security awareness.
Mitigation strategies for CVE-2017-18447 primarily focus on upgrading to cPanel version 64.0.21 or later, which includes proper access control implementations for the ClamScanner_getsocket API. Organizations should also implement additional security measures such as disabling demo accounts when not actively needed, implementing network-level restrictions on API endpoints, and conducting regular security audits of API access controls. The remediation process should include comprehensive testing to ensure that the upgrade does not disrupt legitimate functionality while also verifying that proper access controls are now enforced. Security teams should also consider implementing intrusion detection systems to monitor for suspicious API access patterns and establish incident response procedures for potential exploitation attempts. This vulnerability highlights the importance of following security best practices outlined in frameworks such as NIST SP 800-53, which emphasizes the need for proper access control mechanisms and regular vulnerability assessments to prevent unauthorized system access and privilege escalation attacks.