CVE-2018-20894 in cPanel
Summary
by MITRE
cPanel before 74.0.0 makes web-site contents accessible to other local users via Git repositories (SEC-443).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2018-20894 represents a critical access control flaw in cPanel versions prior to 74.0.0 that allows local users to gain unauthorized access to website contents belonging to other users through Git repository exposure. This issue stems from inadequate permission controls within the cPanel Git implementation, creating a privilege escalation scenario where malicious local users can exploit the system to access sensitive data and resources that should remain isolated to individual user accounts. The vulnerability specifically impacts shared hosting environments where multiple users operate under a single cPanel instance, fundamentally undermining the security isolation that should exist between different user accounts.
The technical root cause of this vulnerability lies in the improper handling of Git repository permissions and access controls within cPanel's implementation. When users create Git repositories for their websites, the system fails to properly enforce user boundaries, allowing one user's Git repository to be accessible by other local users on the same system. This occurs because the Git repository directories are not properly secured with appropriate file system permissions or access control lists that would prevent cross-user access. The flaw essentially creates a path traversal or directory traversal vulnerability within the Git management functionality, enabling unauthorized data exposure through the version control system that should be isolated to individual user contexts.
The operational impact of this vulnerability extends beyond simple data exposure to encompass potential system compromise and data integrity violations. Local users with access to the compromised system can extract sensitive information including source code, configuration files, database credentials, and potentially user data from other accounts. This exposure can lead to credential theft, service disruption, and potential lateral movement within the compromised hosting environment. The vulnerability affects the fundamental security model of shared hosting environments where user isolation is paramount, potentially enabling attackers to gather intelligence for further attacks or to compromise multiple user accounts simultaneously. Organizations relying on cPanel for hosting services face significant risk of data breaches and compliance violations when this vulnerability exists in their systems.
Mitigation strategies for CVE-2018-20894 require immediate attention and systematic approach to address the underlying access control issues. The primary recommendation involves upgrading cPanel to version 74.0.0 or later, which includes proper Git repository permission controls and user isolation mechanisms. System administrators should also implement additional security measures including regular file system permission audits, monitoring for unauthorized Git repository access attempts, and implementing proper logging and alerting for suspicious activities. Organizations should conduct comprehensive vulnerability assessments to identify any existing exposure and ensure that Git repositories are properly secured with appropriate access controls. This vulnerability aligns with CWE-284, which addresses improper access control, and may be categorized under ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, emphasizing the need for comprehensive security measures beyond simple patching.