CVE-2018-20938 in cPanel
Summary
by MITRE
cPanel before 68.0.27 does not enforce ownership during addpkgext and delpkgext WHM API calls (SEC-324).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2018-20938 represents a critical authorization flaw within cPanel's WHM API implementation that affects versions prior to 68.0.27. This issue specifically targets the addpkgext and delpkgext API endpoints, which are used to manage package extensions within the cPanel hosting environment. The vulnerability stems from insufficient validation of user ownership permissions during these administrative operations, creating a potential pathway for unauthorized privilege escalation and resource manipulation. The flaw was classified as SEC-324 within cPanel's internal security tracking system, indicating its significance in the context of administrative access controls.
The technical nature of this vulnerability lies in the absence of proper ownership verification mechanisms within the WHM API calls. When administrators execute addpkgext or delpkgext operations, the system should verify that the requesting user has legitimate ownership or administrative rights over the target package or extension being modified. However, in affected versions, cPanel fails to enforce these ownership checks, allowing malicious actors or compromised accounts with lower privileges to manipulate package extensions that they should not have access to. This represents a direct violation of the principle of least privilege and creates opportunities for unauthorized system modifications that could compromise entire hosting environments.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially escalate their privileges within the hosting infrastructure. An attacker who gains access to a lower-privileged account could leverage this flaw to modify package configurations, potentially creating backdoors or altering system settings that affect multiple users. The vulnerability particularly impacts shared hosting environments where multiple customers share the same server resources, as it could allow one user to manipulate another user's package extensions or gain access to restricted system resources. This creates a significant risk for hosting providers who rely on cPanel's administrative controls to maintain proper isolation between customer accounts.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control issues, and maps to ATT&CK techniques related to privilege escalation and persistence. The flaw demonstrates how API endpoint validation failures can create persistent security risks that may remain undetected for extended periods. Organizations using affected cPanel versions should immediately implement mitigations including upgrading to version 68.0.27 or later, implementing additional monitoring for suspicious API activity, and conducting thorough audits of package extension configurations. The vulnerability also underscores the importance of proper input validation and access control enforcement in administrative APIs, as these systems serve as critical attack surfaces for malicious actors seeking to compromise hosting infrastructure. Regular security assessments of API endpoints and mandatory patch management procedures are essential to prevent exploitation of similar authorization flaws in other system components.