CVE-2016-10793 in cPanel
Summary
by MITRE
cPanel before 59.9999.145 allows arbitrary code execution due to an incorrect #! in Mail::SPF scripts (SEC-152).
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2016-10793 represents a critical security flaw in cPanel versions prior to 59.9999.145 that enables arbitrary code execution through improper handling of shebang directives in Mail::SPF scripts. This issue stems from a fundamental misconfiguration in the execution environment where the shebang line containing the interpreter path is incorrectly specified, creating a potential attack vector for privilege escalation and system compromise. The vulnerability specifically affects the Mail::SPF module which is integral to email server functionality and SPF record validation processes within cPanel environments.
The technical flaw manifests through an incorrect #! directive in the Mail::SPF scripts that allows for command injection and arbitrary code execution. When cPanel processes email-related SPF validation requests, the malformed shebang line can be manipulated by attackers to execute malicious commands with elevated privileges. This misconfiguration essentially creates a path traversal or command injection vulnerability where an attacker can influence the execution flow of system commands through the improperly validated interpreter specification. The vulnerability operates at the system level where the mail server components interact with the underlying operating system, making it particularly dangerous for web hosting environments where multiple users share the same infrastructure.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and unauthorized access to sensitive data. Attackers can leverage this flaw to gain root privileges on affected systems, potentially leading to data exfiltration, service disruption, or establishment of persistent backdoors. The vulnerability affects cPanel installations where the Mail::SPF functionality is enabled, which is standard in most hosting environments, making it a widespread concern for system administrators managing multiple client accounts. The attack surface is particularly large in shared hosting environments where the compromise of one user's email services could potentially lead to broader system infiltration.
This vulnerability aligns with CWE-78 and CWE-74 categories from the Common Weakness Enumeration, specifically addressing issues related to command injection and improper input validation in system command execution contexts. The flaw demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries use legitimate system tools to execute malicious code. Organizations should prioritize immediate patching to address this vulnerability, as the window for exploitation remains open in unpatched systems. The remediation involves upgrading to cPanel version 59.9999.145 or later, which contains the necessary fixes to correct the shebang directive handling in Mail::SPF scripts. Security teams should also implement monitoring for suspicious command execution patterns and review system logs for potential exploitation attempts. Additionally, network segmentation and access controls should be reinforced to limit the potential impact should exploitation occur, as this vulnerability could enable attackers to move laterally within compromised environments.