CVE-2018-20873 in ClamAV
Summary
by MITRE
cPanel before 74.0.8 allows local users to disable the ClamAV daemon (SEC-409).
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Analysis
by VulDB Data Team • 07/17/2020
The vulnerability identified as CVE-2018-20873 affects cPanel versions prior to 74.0.8 and represents a significant local privilege escalation issue that undermines the security posture of web hosting environments. This flaw allows local users to disable the ClamAV daemon, which serves as a critical antivirus service for detecting malicious files and malware within hosted environments. The vulnerability specifically relates to improper access controls and privilege management within the cPanel administrative interface, creating a pathway for unauthorized local users to manipulate core security services.
The technical implementation of this vulnerability stems from insufficient validation of user permissions when attempting to manage the ClamAV daemon service. Local users with minimal privileges can exploit this weakness to disable security monitoring capabilities that are essential for maintaining the integrity of hosted websites and email services. This represents a direct violation of the principle of least privilege and undermines the defense-in-depth strategy that organizations rely upon for securing their hosting infrastructure. The flaw essentially allows attackers who have gained access to a low-privilege account to disable critical security monitoring services, potentially enabling further attacks without detection.
The operational impact of this vulnerability extends beyond simple service disruption to encompass significant security implications for hosted environments. When the ClamAV daemon is disabled, organizations lose real-time malware detection capabilities that protect against various threats including web shells, malicious scripts, and other forms of automated attacks targeting hosted applications. This vulnerability particularly affects shared hosting environments where multiple users operate on the same infrastructure, as it allows one compromised user to potentially disable security monitoring for all users on that system. The disruption of antivirus services creates a window of opportunity for attackers to establish persistence and conduct further malicious activities without the protective layer of automated malware detection.
Organizations should implement immediate mitigations including upgrading to cPanel version 74.0.8 or later, which contains the necessary patches to address this vulnerability. System administrators should also conduct thorough audits of local user accounts and implement stricter access controls to limit potential exploitation vectors. The vulnerability aligns with CWE-276, which addresses incorrect permissions for critical resources, and represents a classic example of how insufficient access controls can lead to privilege escalation and service disruption. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1070 (Indicator Removal on Host) as it enables attackers to disable security monitoring and potentially hide their activities. Additionally, this issue demonstrates the importance of maintaining up-to-date security software and proper privilege management within hosting environments to prevent local users from compromising core security services that protect against broader threats.