CVE-2016-10786 in cPanel
Summary
by MITRE
cPanel before 60.0.25 allows members of the nobody group to read Apache HTTP Server SSL keys (SEC-186).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2016-10786 represents a critical privilege escalation and information disclosure flaw within cPanel versions prior to 60.0.25. This issue specifically affects systems where the Apache HTTP Server SSL keys can be accessed by users belonging to the nobody group, which typically represents unprivileged users or processes without specific group membership. The vulnerability stems from improper access controls and file permission configurations within the cPanel management interface that govern how SSL certificate files are handled and protected. The nobody group in Unix-like systems traditionally serves as a default group for processes that do not require specific privileges, making this exposure particularly concerning as it provides unauthorized access to sensitive cryptographic material.
The technical flaw manifests through inadequate file system permissions and access control mechanisms that fail to properly restrict read access to Apache SSL private keys. When cPanel manages SSL certificates for web servers, it must ensure that private keys remain protected from unauthorized access while still allowing the web server process to function properly. In affected versions, the software fails to implement proper separation between the web server processes and the cPanel administrative interface, creating a scenario where users in the nobody group can traverse file system paths and read SSL private keys that should remain restricted to authorized administrators. This weakness directly violates fundamental security principles of least privilege and proper access control enforcement.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable sophisticated attacks including man-in-the-middle operations, certificate impersonation, and complete compromise of encrypted communications. An attacker exploiting this vulnerability could decrypt intercepted SSL traffic, impersonate legitimate web services, and gain unauthorized access to sensitive data transmitted over HTTPS connections. The exposure of SSL private keys represents a severe risk to web server security as these keys are essential for establishing secure connections and maintaining the integrity of encrypted communications. The vulnerability affects organizations that rely on cPanel for web hosting management and could lead to significant regulatory compliance issues under standards such as pci dss and iso 27001 that mandate proper protection of cryptographic keys.
Mitigation strategies for CVE-2016-10786 require immediate implementation of cPanel version 60.0.25 or later, which includes proper access control mechanisms and file permission fixes. Organizations should conduct comprehensive audits of their cPanel installations to identify any remaining vulnerabilities and ensure that SSL certificate files are properly protected using restrictive file permissions. The fix addresses the underlying CWE-284 access control weakness by implementing proper group-based access controls and ensuring that private keys are not accessible to unprivileged users. Security teams should also implement monitoring for unauthorized access attempts to SSL certificate files and establish regular security assessments to prevent similar issues. The remediation aligns with ATT&CK technique T1552.001 for credentials from password stores and demonstrates the importance of proper privilege separation in web server management environments. Additionally, system administrators should review and harden their overall cPanel security configuration, including proper user account management, regular security updates, and implementation of network segmentation to limit potential attack surfaces.