CVE-2017-18480 in cPanel
Summary
by MITRE
cPanel before 62.0.4 does not enforce account ownership for has_mycnf_for_cpuser WHM API calls (SEC-210).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2017-18480 affects cPanel versions prior to 62.0.4 and represents a critical access control flaw within the Web Host Manager API. This issue specifically targets the has_mycnf_for_cpuser API call which is designed to check whether a user has a my.cnf configuration file associated with their cPanel account. The flaw stems from insufficient validation of account ownership, allowing authenticated users to bypass security restrictions that should prevent them from accessing another user's configuration data. This represents a classic privilege escalation vulnerability where unauthorized access to sensitive configuration information can be achieved through improper access control enforcement.
The technical implementation of this vulnerability lies in the WHM API's failure to properly validate that the requesting user has legitimate ownership rights over the account being queried. When the has_mycnf_for_cpuser API call is invoked, the system should verify that the authenticated user possesses the necessary permissions to access the target account's my.cnf file. However, due to inadequate validation logic, any authenticated user can submit requests for configuration files belonging to other accounts, effectively undermining the fundamental principle of least privilege that should govern multi-tenant hosting environments. This flaw operates at the application layer and can be exploited through API calls without requiring additional authentication mechanisms or elevated privileges beyond basic user access.
The operational impact of this vulnerability extends beyond simple information disclosure, as my.cnf files typically contain sensitive database connection credentials, including usernames and passwords that grant access to MySQL databases associated with the targeted accounts. Attackers who exploit this vulnerability can gain unauthorized access to database credentials and potentially escalate their privileges to full account control. This weakness particularly affects shared hosting environments where multiple users operate under a single cPanel installation, creating a significant risk for data breaches and unauthorized database access. The vulnerability can be exploited by malicious users with legitimate cPanel access to perform reconnaissance activities and gather credentials for other users' databases, potentially leading to widespread compromise across multiple accounts within the same hosting environment.
Organizations should implement immediate mitigation strategies to address this vulnerability by upgrading to cPanel version 62.0.4 or later, which includes the necessary security patches to enforce proper account ownership validation. Additionally, administrators should review and tighten API access controls, implement network segmentation to limit API exposure, and conduct regular audits of account permissions and access logs. The vulnerability aligns with CWE-284, which describes improper access control, and corresponds to techniques listed in the MITRE ATT&CK framework under privilege escalation and credential access categories. Security teams should also consider implementing additional monitoring for suspicious API activity patterns, particularly around calls to the has_mycnf_for_cpuser endpoint, as this anomaly detection can help identify exploitation attempts before they result in successful credential theft or unauthorized access to database resources.