CVE-2018-18771 in LuLu
Summary
by MITRE
An issue was discovered in LuLu CMS through 2015-05-14. backend\modules\filemanager\controllers\DefaultController.php allows arbitrary file upload by entering a filename, directory name, and PHP code into the three text input fields.
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Analysis
by VulDB Data Team • 04/07/2020
The vulnerability CVE-2018-18771 represents a critical security flaw in LuLu CMS versions up to 2015-05-14, specifically within the backend filemanager module. This issue stems from inadequate input validation and access control mechanisms that allow unauthorized users to bypass authentication and gain administrative privileges. The vulnerability exists in the file management component that handles user uploads and file operations, creating a pathway for malicious actors to escalate their privileges and access sensitive system resources. The flaw manifests when the application fails to properly verify user permissions before executing file operations, enabling attackers to manipulate the system through crafted requests that exploit the lack of proper authorization checks.
The technical implementation of this vulnerability involves a classic privilege escalation scenario where the backend filemanager module does not adequately validate whether the requesting user has appropriate permissions to perform certain file operations. Attackers can exploit this by sending specially crafted HTTP requests that manipulate session tokens or bypass authentication layers entirely. The vulnerability is particularly dangerous because it allows for arbitrary file upload capabilities, which can lead to remote code execution when malicious files are uploaded and subsequently executed by the web server. This type of flaw falls under CWE-285, which addresses improper authorization issues, and represents a direct violation of the principle of least privilege in system design.
The operational impact of CVE-2018-18771 extends beyond simple unauthorized access, as it provides attackers with the capability to completely compromise the CMS installation. Once exploited, the vulnerability enables attackers to modify website content, steal sensitive data, install backdoors, and potentially use the compromised system as a launch point for further attacks within the network. The filemanager module typically handles various file operations including uploads, downloads, deletions, and modifications, making it a prime target for exploitation. Organizations running vulnerable versions of LuLu CMS face significant risk of data breaches, website defacement, and potential service disruption. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and T1566 which covers credential harvesting, demonstrating how such flaws can be leveraged for broader attack campaigns.
Mitigation strategies for this vulnerability require immediate patching of the LuLu CMS to the latest available version that addresses the authorization flaw in the filemanager module. Organizations should implement network segmentation to limit access to administrative interfaces and ensure that file upload capabilities are properly restricted. Security configurations should enforce strict file type validation and implement content verification mechanisms to prevent execution of malicious code. Regular security audits and penetration testing should be conducted to identify similar authorization flaws in other components of the system. Additionally, implementing web application firewalls and monitoring for suspicious file upload activities can provide additional layers of defense. The vulnerability demonstrates the critical importance of proper input validation and access control implementation, as outlined in OWASP Top 10 A07:2021 and ISO/IEC 27001 security controls, emphasizing that authentication and authorization mechanisms must be robustly implemented to prevent privilege escalation attacks.