CVE-2018-18083 in DuomiCMS
Summary
by MITRE
An issue was discovered in DuomiCMS 3.0. Remote PHP code execution is possible via the search.php searchword parameter because "eval" is used during "if" processing.
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Analysis
by VulDB Data Team • 04/01/2020
The vulnerability identified as CVE-2018-18083 represents a critical remote code execution flaw in DuomiCMS version 3.0 that stems from improper input validation and dangerous PHP function usage. This vulnerability exists within the search functionality of the content management system where user-supplied input is directly processed without adequate sanitization, creating an avenue for malicious actors to inject and execute arbitrary PHP code on the affected server. The flaw specifically manifests in the search.php script where the searchword parameter is processed through conditional logic that inadvertently invokes the eval() function, transforming legitimate search queries into potential attack vectors.
The technical implementation of this vulnerability demonstrates a classic improper input validation issue that aligns with CWE-20, which covers improper input validation in software systems. The use of eval() within conditional processing creates a dangerous execution environment where attacker-controlled data can be interpreted as PHP code rather than simple text input. This particular implementation pattern violates fundamental security principles by allowing user input to directly influence the execution flow of the application, enabling arbitrary code execution with the privileges of the web server process. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in environments where the CMS is publicly accessible.
From an operational perspective, this vulnerability presents significant risk to organizations utilizing DuomiCMS 3.0 as it allows remote attackers to execute arbitrary code on the target system without requiring any prior authentication credentials. The impact extends beyond simple code execution to potentially enable full system compromise, data exfiltration, and persistence mechanisms. Attackers can leverage this vulnerability to establish backdoors, deploy malware, or gain access to sensitive information stored within the CMS. The attack surface is particularly concerning given that the vulnerability exists in a core functionality component - the search feature - which is typically enabled and accessible to all users, making exploitation straightforward and widespread.
Security mitigations for CVE-2018-18083 should focus on immediate patching of the DuomiCMS 3.0 installation to the latest available version that addresses this specific vulnerability. Organizations should implement input validation measures that sanitize all user-supplied data before processing, particularly within search parameters and other dynamic input fields. The use of eval() function should be eliminated from all application code, as it represents a fundamental security risk that cannot be adequately mitigated through input sanitization alone. Network-level protections including web application firewalls and intrusion detection systems can provide additional defense-in-depth measures, though they should not be relied upon as the primary mitigation strategy. The vulnerability also highlights the importance of following secure coding practices and adhering to the principle of least privilege when implementing application functionality, particularly in search and processing components that handle external input.
This vulnerability aligns with several ATT&CK framework techniques including T1059.007 for command and scripting interpreter and T1078 for valid accounts, as exploitation enables attackers to execute system commands and potentially maintain persistent access. The attack chain typically involves initial reconnaissance, exploitation of the search functionality, and subsequent system compromise. Organizations should also consider implementing application whitelisting policies and regular security assessments to identify similar vulnerabilities in other applications and systems that may be susceptible to similar attack patterns involving dynamic code execution and improper input handling.