CVE-2019-14746 in KuaiFanCMS
Summary
by MITRE
A issue was discovered in KuaiFanCMS 5.0. It allows eval injection by placing PHP code in the install.php db_name parameter and then making a config.php request.
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Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2019-14746 represents a critical server-side code injection flaw in KuaiFanCMS version 5.0 that fundamentally undermines the application's security posture. This issue stems from inadequate input validation and sanitization within the installation process, specifically targeting the db_name parameter in the install.php file. The flaw enables attackers to execute arbitrary PHP code through malicious input manipulation, creating a persistent backdoor opportunity within the targeted system. The vulnerability manifests when an attacker crafts malicious PHP code within the database name parameter during installation, which then gets executed when the application attempts to read or process the configuration file.
The technical implementation of this vulnerability aligns with CWE-94, which categorizes improper execution of dynamic code, and demonstrates how insecure parameter handling can lead to complete system compromise. When the install.php script processes the db_name parameter without proper sanitization, it inadvertently executes the injected PHP code, allowing attackers to perform operations such as file manipulation, database access, or even remote command execution depending on the server configuration. The subsequent config.php request serves as the execution vector where the malicious payload is triggered, making this a multi-stage attack that requires both initial code injection and subsequent exploitation. This vulnerability operates at the application layer and can be classified under the ATT&CK technique T1059.007 for dynamic code execution, making it particularly dangerous as it bypasses traditional security controls that might monitor for known malicious patterns.
The operational impact of CVE-2019-14746 extends far beyond simple data theft, as it provides attackers with complete administrative control over affected systems. Successful exploitation allows unauthorized users to establish persistent access, modify or delete critical application data, and potentially use the compromised system as a launch point for further attacks within the network infrastructure. The vulnerability's persistence is enhanced by the fact that the injected code remains active even after the initial installation process, making it difficult to detect and remove without complete system reinstallation. Organizations running KuaiFanCMS 5.0 are particularly vulnerable because the flaw exists in the core installation logic, meaning that any system with this version deployed is at risk regardless of other security measures in place. The attack requires minimal sophistication from threat actors, making it attractive for both automated exploitation tools and targeted attacks against vulnerable web applications.
Mitigation strategies for CVE-2019-14746 must address both immediate remediation and long-term security improvements. The primary recommendation involves upgrading to a patched version of KuaiFanCMS that properly validates and sanitizes all user input parameters, particularly those used during installation processes. Organizations should implement strict input validation mechanisms that reject any non-standard characters or code sequences in database name fields and other critical parameters. Network-based protections such as web application firewalls can help detect and block malicious requests attempting to exploit this vulnerability, though they should not be considered a complete solution. Regular security auditing of application code and input handling mechanisms is essential to prevent similar vulnerabilities from emerging in the future. Additionally, implementing principle of least privilege for database connections and application services reduces the potential impact of successful exploitation attempts, while comprehensive monitoring and logging of installation activities can help detect unauthorized modifications to system configuration files.