CVE-2017-18401 in cPanel
Summary
by MITRE
cPanel before 68.0.15 allows user accounts to be partially created with invalid username formats (SEC-334).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability identified as CVE-2017-18401 affects cPanel versions prior to 68.0.15 and represents a critical authentication and account management flaw that undermines the system's user account creation process. This issue falls under the category of weak input validation and authorization controls, specifically impacting the integrity of user account provisioning within the cPanel environment. The vulnerability allows malicious actors or unauthorized users to create user accounts with invalid username formats, effectively bypassing the system's normal account validation mechanisms and potentially enabling privilege escalation or unauthorized access to system resources.
The technical implementation of this flaw stems from insufficient validation of username formats during the account creation process. When users attempt to create accounts with malformed or non-compliant usernames, the system fails to properly enforce naming conventions that are typically required for valid user accounts. This weakness creates a scenario where accounts can be partially created with invalid identifiers, potentially allowing attackers to exploit the system's lenient validation rules to establish accounts that may not be properly authenticated or authorized. The vulnerability specifically relates to the account creation API or interface where username validation occurs before final account establishment, leaving a window of opportunity for malformed identifiers to persist in the system.
The operational impact of CVE-2017-18401 extends beyond simple account creation issues and can lead to significant security implications within hosting environments that rely on cPanel for user management. Attackers could potentially exploit this vulnerability to create accounts with unexpected username formats that might bypass certain security controls or access restrictions. This flaw could enable unauthorized users to gain access to system resources, manipulate account permissions, or potentially escalate privileges within the hosting environment. The vulnerability also creates potential confusion in system logs and user management interfaces where invalid accounts might not be properly handled or flagged for review, making it difficult for administrators to maintain proper security posture and audit trails.
Organizations running cPanel versions prior to 68.0.15 should prioritize immediate remediation through the application of the vendor-provided security patch that addresses this validation weakness. The fix typically involves strengthening the username validation logic to ensure all account creation attempts are properly validated before account completion, implementing stricter compliance checks for username formats, and ensuring that invalid identifiers are rejected at the earliest possible stage of account provisioning. System administrators should also conduct comprehensive audits of existing user accounts to identify and remove any accounts that may have been created with invalid username formats during the vulnerable period, implementing additional monitoring and alerting mechanisms to detect anomalous account creation patterns.
This vulnerability aligns with CWE-20, which describes "Improper Input Validation" and represents a failure in the system's ability to properly validate user inputs during account creation processes. From an adversarial perspective, this flaw maps to ATT&CK technique T1133, which involves unauthorized access to system accounts and could enable threat actors to establish persistent access through compromised or improperly validated user accounts. The vulnerability demonstrates the critical importance of input validation in authentication systems and highlights how seemingly minor validation gaps can create significant security risks in hosting and management platforms where user account creation is a fundamental operational function.