CVE-2018-10086 in CMS Made Simple
Summary
by MITRE
CMS Made Simple (CMSMS) through 2.2.7 contains an arbitrary code execution vulnerability in the admin dashboard because the implementation uses "eval('function testfunction'.rand()" and it is possible to bypass certain restrictions on these "testfunction" functions.
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Analysis
by VulDB Data Team • 01/24/2020
The CVE-2018-10086 vulnerability represents a critical arbitrary code execution flaw in CMS Made Simple versions up to 2.2.7 that fundamentally undermines the security posture of affected systems. This vulnerability resides within the admin dashboard functionality where the application employs a dangerous coding pattern that directly invokes the eval() function with dynamically generated code strings. The implementation specifically utilizes eval('function testfunction'.rand()) which creates a pathway for malicious actors to inject and execute arbitrary PHP code within the context of the web server. The vulnerability stems from insufficient input validation and sanitization mechanisms that fail to properly restrict the content of the dynamically generated function names and their associated code execution contexts.
The technical exploitation of this vulnerability occurs through a bypass mechanism that allows attackers to circumvent existing security restrictions placed on the testfunction functions. This bypass capability arises from the flawed implementation where the randomization process does not adequately prevent predictable or controllable inputs that could be manipulated by an attacker. The vulnerability operates under CWE-94 which classifies it as an "Improper Control of Generation of Code ('Code Injection')" allowing attackers to execute malicious code with the privileges of the web server. The attack vector specifically targets the administrative interface where legitimate users with appropriate permissions can inadvertently trigger the vulnerable code path through manipulated input parameters.
The operational impact of this vulnerability extends far beyond simple code execution as it provides attackers with complete system compromise capabilities. Once exploited, attackers can execute arbitrary commands on the affected server, potentially leading to full system takeover, data exfiltration, and persistence mechanisms. The vulnerability affects organizations using CMS Made Simple in production environments where administrative access might be compromised or where attackers can gain access to administrative accounts through other means. The impact is particularly severe because the vulnerability exists within the admin dashboard where administrative privileges are typically granted, making it a prime target for privilege escalation attacks. This flaw directly aligns with ATT&CK technique T1059.006 which covers "Command and Scripting Interpreter: PowerShell" and T1078 which addresses "Valid Accounts" and can be leveraged to maintain persistent access.
Organizations should implement immediate mitigations including upgrading to CMS Made Simple versions that address this vulnerability, as the original vulnerable code pattern must be completely removed from the application. Network segmentation and access controls should be strengthened to limit administrative access to only trusted users and systems. Input validation and sanitization measures must be enhanced to prevent any dynamic code generation from being executed without proper verification. The implementation of web application firewalls and runtime application self-protection mechanisms can provide additional layers of defense against exploitation attempts. Regular security auditing and code review processes should be implemented to identify similar patterns that might exist in other parts of the application. System monitoring should be enhanced to detect unusual command execution patterns that might indicate exploitation attempts, and security patches should be applied immediately upon availability of fixed versions.