CVE-2016-10859 in cPanel
Summary
by MITRE
cPanel before 11.54.0.0 allows unauthorized password changes via Webmail API commands (SEC-65).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10859 represents a critical authentication bypass flaw in cPanel versions prior to 11.54.0.0 that specifically affects the Webmail API functionality. This issue enables attackers to perform unauthorized password changes against user accounts through the webmail interface, fundamentally compromising the integrity of the authentication system. The vulnerability stems from insufficient input validation and authorization checks within the API commands that handle password modification operations, creating an attack vector that can be exploited without proper credentials or authentication tokens.
The technical implementation of this flaw occurs within the Webmail API subsystem where specific commands designed for password management fail to properly verify user permissions or validate the authenticity of requests. Attackers can manipulate API calls to change passwords for arbitrary user accounts by leveraging the lack of proper authorization controls. This vulnerability operates at the application layer and can be exploited through HTTP requests that target the webmail API endpoints, making it particularly dangerous as it can be executed remotely without requiring direct system access or elevated privileges.
The operational impact of this vulnerability extends beyond simple credential compromise, as it allows attackers to gain persistent access to user mailboxes and potentially escalate privileges within the cPanel environment. Once an attacker successfully changes a password through this vulnerability, they can access email accounts, view sensitive communications, and potentially use those credentials to access other systems where the same passwords may be reused. The attack can be automated and executed at scale, making it particularly dangerous for hosting providers who manage multiple user accounts through a single cPanel instance.
Security professionals should recognize this vulnerability as aligning with CWE-287 which addresses improper authentication issues in software systems. The flaw also corresponds to techniques described in the MITRE ATT&CK framework under credential access and privilege escalation tactics. Organizations affected by this vulnerability should implement immediate mitigations including upgrading to cPanel version 11.54.0.0 or later, implementing additional API rate limiting controls, and conducting thorough security audits of their webmail configurations. Network segmentation and monitoring of API access patterns should be enhanced to detect potential exploitation attempts, while administrators should review and tighten access controls for all webmail API endpoints to prevent unauthorized modifications to user accounts.
The remediation process requires comprehensive system updates and configuration reviews to ensure that all API endpoints properly validate user credentials and authorization tokens before executing sensitive operations. Organizations should also implement logging and monitoring solutions that can detect anomalous password change patterns and alert security teams to potential exploitation attempts. Regular vulnerability assessments should be conducted to identify similar authentication bypass vulnerabilities in other web applications and services that may present similar attack surfaces to the cPanel environment.