CVE-2016-10826 in cPanel
Summary
by MITRE
cPanel before 55.9999.141 allows attackers to bypass Two Factor Authentication via DNS clustering requests (SEC-93).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10826 represents a critical security flaw in cPanel software versions prior to 55.9999.141 that undermines the integrity of the Two Factor Authentication (2FA) mechanism through a sophisticated bypass technique leveraging DNS clustering requests. This vulnerability specifically targets the authentication flow within cPanel's administrative interface, creating a pathway for malicious actors to circumvent the additional security layer that should protect against unauthorized access attempts. The flaw operates by exploiting the trust relationship between clustered DNS servers and the cPanel management system, allowing attackers to authenticate without proper verification of their second factor credentials.
The technical implementation of this vulnerability stems from inadequate input validation and authentication flow control within the DNS clustering functionality of cPanel. When DNS clustering requests are processed, the system fails to properly validate whether the requesting entity has successfully completed the Two Factor Authentication process. This oversight creates a window of opportunity where an attacker can manipulate DNS cluster communications to gain access to the administrative interface without providing the required second factor authentication tokens. The vulnerability specifically affects systems that utilize cPanel's DNS clustering features, which are commonly deployed in enterprise environments where multiple servers coordinate DNS management operations.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it fundamentally compromises the security posture of systems relying on cPanel for web hosting management. Attackers who successfully exploit this vulnerability can gain full administrative control over affected cPanel installations, potentially leading to data breaches, service disruption, and unauthorized modifications to web hosting configurations. The implications are particularly severe in environments where cPanel manages critical customer data, as the bypass allows attackers to access sensitive information without detection. This vulnerability directly violates security principles outlined in the Common Weakness Enumeration framework, specifically aligning with CWE-287 which addresses improper authentication scenarios, and represents a significant deviation from the expected security controls defined in the MITRE ATT&CK framework under the credential access category.
Organizations affected by this vulnerability should immediately implement the recommended mitigation strategies including upgrading to cPanel version 55.9999.141 or later, which contains the necessary patches to address the authentication bypass mechanism. Additionally, system administrators should review their DNS clustering configurations to ensure that proper access controls are in place and that unnecessary trust relationships are minimized. Network segmentation and monitoring solutions should be enhanced to detect unusual DNS clustering traffic patterns that might indicate exploitation attempts. The remediation process should also include comprehensive security auditing of all cPanel installations to identify potential secondary impacts from the vulnerability. Security teams should implement continuous monitoring for suspicious authentication patterns and establish incident response procedures specifically tailored to address credential bypass scenarios in web hosting management platforms.