CVE-2017-18434 in cPanel
Summary
by MITRE
cPanel before 64.0.21 allows code execution in the context of the root account via a SET_VHOST_LANG_PACKAGE multilang adminbin call (SEC-237).
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Analysis
by VulDB Data Team • 07/19/2020
The vulnerability CVE-2017-18434 represents a critical privilege escalation flaw within cPanel software versions prior to 64.0.21. This vulnerability specifically targets the multilang adminbin functionality and exploits a weakness in the handling of virtual host language package settings. The issue manifests as a code execution vulnerability that operates with root-level privileges, making it particularly dangerous for system administrators who rely on cPanel for web hosting management. The vulnerability was identified and documented as SEC-237 within cPanel's security advisory framework.
The technical implementation of this vulnerability occurs through the SET_VHOST_LANG_PACKAGE function within the multilang adminbin component. This function processes language package configurations for virtual hosts without proper input validation or sanitization. Attackers can manipulate the input parameters to inject malicious code that executes with the privileges of the root account. The flaw stems from insufficient parameter validation and improper privilege handling within the administrative binary interface. This allows an authenticated attacker with administrative access to escalate their privileges to root level and execute arbitrary commands on the affected system.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the compromised system. With root-level access, adversaries can modify system files, install backdoors, exfiltrate sensitive data, and potentially use the compromised server as a launch point for further attacks within the network. The vulnerability affects the core cPanel functionality that manages virtual host configurations, making it particularly impactful for hosting providers and system administrators who depend on cPanel for managing multiple domains and user accounts. The root privilege execution capability means that attackers can bypass standard security controls and access all system resources, including databases, user files, and system configurations.
Mitigation strategies for CVE-2017-18434 primarily focus on immediate software updates to cPanel version 64.0.21 or later, which includes patches addressing the input validation issues in the multilang adminbin functionality. Organizations should implement comprehensive monitoring of administrative access logs to detect suspicious activity related to multilang configuration changes. The vulnerability aligns with CWE-20 Improper Input Validation and CWE-78 Improper Neutralization of Special Elements used in an OS Command, both of which are commonly exploited in privilege escalation attacks. Security professionals should also consider implementing network segmentation and least privilege principles to limit the potential damage from successful exploitation. This vulnerability demonstrates the critical importance of keeping administrative software updated and validating all inputs in system management interfaces. The ATT&CK framework categorizes this as a privilege escalation technique using administrative tools, specifically targeting the execution of commands with elevated privileges through vulnerable system binaries.