CVE-2018-17856 in Joomla
Summary
by MITRE
An issue was discovered in Joomla! before 3.8.13. com_joomlaupdate allows the execution of arbitrary code. The default ACL config enabled the ability of Administrator-level users to access com_joomlaupdate and trigger code execution.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-17856 represents a critical arbitrary code execution flaw within the Joomla core updates. The vulnerability stems from improper access control mechanisms that fail to adequately restrict administrative privileges, creating a dangerous pathway for malicious actors to escalate their privileges and execute arbitrary code on affected systems.
The technical implementation of this vulnerability involves a default access control list configuration that incorrectly grants administrator-level users the ability to access the com_joomlaupdate component without proper authorization checks. This misconfiguration allows authenticated users with administrative privileges to trigger code execution through the update component, which typically should only be accessible to system administrators with explicit permissions. The flaw operates at the application layer and leverages the trust relationship between the web application and its authenticated users, making it particularly dangerous in environments where administrative accounts may be compromised or where privilege escalation attacks are possible.
From an operational impact perspective, this vulnerability creates significant risk for Joomla versions face immediate risk of unauthorized access and potential data breaches, as the vulnerability does not require special privileges beyond an existing administrative account. This makes it particularly attractive to attackers who may have already gained access to administrative credentials through other means such as credential stuffing, phishing, or other initial compromise techniques.
The vulnerability aligns with CWE-284 (Improper Access Control) and represents a classic case of insufficient privilege checks within a web application framework. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1078 (Valid Accounts) and T1059 (Command and Scripting Interpreter) as attackers can leverage existing administrative credentials to execute malicious code. Organizations should immediately apply the security patch released by Joomla! for version 3.8.13 which addresses the improper access control configuration. Additional mitigations include implementing network segmentation, monitoring for unusual administrative activity, and ensuring that administrative accounts are protected with strong authentication mechanisms including multi-factor authentication. Regular security audits of access control configurations and timely patch management processes are essential to prevent exploitation of similar vulnerabilities in the future.