CVE-2016-10787 in cPanel
Summary
by MITRE
The Host Access Control feature in cPanel before 60.0.25 mishandles actionless host.deny entries (SEC-187).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2016-10787 resides within the Host Access Control functionality of cPanel software versions prior to 60.0.25. This issue specifically pertains to how the system processes host.deny entries that lack explicit action specifications, creating a potential security risk that could allow unauthorized access to systems protected by cPanel's access control mechanisms. The problem was categorized as SEC-187 within cPanel's security advisory framework, indicating its significance within the organization's vulnerability management system.
The technical flaw manifests in the improper handling of host.deny configuration entries that do not contain explicit action directives. When cPanel processes these entries, it fails to correctly interpret or enforce access control rules that are missing action specifications, potentially leading to a scenario where entries that should restrict access are either ignored or misinterpreted. This misinterpretation occurs at the configuration parsing level where the system does not properly validate or standardize entries lacking complete action specifications. The vulnerability exploits a gap in input validation and configuration processing that allows malformed or incomplete access control entries to bypass intended security restrictions.
The operational impact of this vulnerability extends beyond simple access control bypasses and represents a significant risk to system security integrity. Attackers could potentially exploit this weakness to gain unauthorized access to cPanel-hosted services by crafting malicious host.deny entries that exploit the actionless entry handling flaw. This vulnerability undermines the fundamental security posture of systems relying on cPanel's Host Access Control feature, potentially allowing unauthorized users to access sensitive web applications, databases, or system resources that should be restricted. The impact is particularly concerning in shared hosting environments where multiple users depend on proper access controls to maintain isolation and security boundaries.
Mitigation strategies for CVE-2016-10787 require immediate system updates to cPanel version 60.0.25 or later, which includes the necessary patches to properly handle actionless host.deny entries. Organizations should conduct comprehensive audits of existing host.deny configurations to identify and correct any entries that may be vulnerable to this flaw, ensuring that all entries contain explicit action specifications. Security teams should implement monitoring procedures to detect unusual access patterns that might indicate exploitation attempts, while also reviewing system logs for evidence of unauthorized access attempts. The vulnerability aligns with CWE-284, which addresses improper access control, and could potentially be leveraged as part of broader attack chains that align with ATT&CK techniques related to privilege escalation and unauthorized access to systems. Organizations should also consider implementing additional security controls such as network segmentation and enhanced logging to reduce the potential impact of any exploitation attempts.