CVE-2018-19367 in Portainer
Summary
by MITRE
Portainer through 1.19.2 provides an API endpoint (/api/users/admin/check) to verify that the admin user is already created. This API endpoint will return 404 if admin was not created and 204 if it was already created. Attackers can set an admin password in the 404 case.
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Analysis
by VulDB Data Team • 06/11/2023
This vulnerability exists in Portainer versions through 1.19.2 where the API endpoint /api/users/admin/check exhibits improper access control behavior that enables account enumeration and privilege escalation. The endpoint's response codes reveal the existence of the admin user account, providing attackers with information about the system's authentication state. When the admin user does not exist, the endpoint returns a 404 status code indicating resource not found, while a 204 status code indicates the user exists. This information disclosure pattern creates a predictable attack surface that adversaries can exploit to determine account existence and subsequently manipulate the system's authentication state.
The technical flaw stems from the application's failure to properly implement secure authentication checks and response handling. The endpoint's behavior violates security principles by exposing account enumeration information through HTTP response codes, which directly relates to CWE-200 Information Exposure and CWE-305 Authentication Bypass. This vulnerability allows attackers to perform account enumeration attacks and potentially gain unauthorized access to administrative privileges. The flaw exists because the system does not implement proper rate limiting or access control measures to prevent unauthorized users from probing the authentication endpoints.
The operational impact of this vulnerability is significant as it enables attackers to perform reconnaissance activities that can lead to full system compromise. An attacker can systematically test the endpoint to determine whether an admin user exists, then exploit the 404 response to set an admin password, effectively bypassing normal authentication mechanisms. This creates a privilege escalation pathway that allows unauthorized users to gain administrative access to the Portainer management interface, potentially leading to complete system compromise. The vulnerability affects organizations that rely on Portainer for container management and orchestration, making it particularly dangerous in environments where container security is critical.
Mitigation strategies should include immediate patching to Portainer version 1.20.0 or later, which resolves this vulnerability through proper authentication handling. Organizations should also implement network segmentation and access controls to limit exposure of the Portainer API endpoints to trusted networks only. Additional security measures include implementing proper rate limiting on API endpoints, enabling authentication for all API access, and monitoring for suspicious API activity patterns. The vulnerability demonstrates the importance of following secure coding practices and implementing proper error handling that does not reveal sensitive information about system state. Organizations should also consider implementing multi-factor authentication and regular security audits to prevent similar issues in other applications. This vulnerability aligns with ATT&CK technique T1078 Valid Accounts, where adversaries use legitimate credentials to gain access to systems, and T1566 Phishing, as attackers may use the information gathered through enumeration to craft targeted attacks against the system.