CVE-2019-16113 in Bludit
Summary
by MITRE
Bludit 3.9.2 allows remote code execution via bl-kernel/ajax/upload-images.php because PHP code can be entered with a .jpg file name, and then this PHP code can write other PHP code to a ../ pathname.
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Analysis
by VulDB Data Team • 06/12/2025
The vulnerability identified as CVE-2019-16113 affects Bludit version 3.9.2 and represents a critical remote code execution flaw that stems from improper file validation and handling within the image upload functionality. This vulnerability exists in the bl-kernel/ajax/upload-images.php script which fails to properly validate file extensions and content, allowing malicious actors to upload PHP code disguised as image files with .jpg extensions. The flaw creates a path traversal condition that enables attackers to write malicious PHP code to directories above the intended upload location, effectively bypassing security restrictions designed to contain file uploads within specific directories.
The technical implementation of this vulnerability involves a combination of file extension manipulation and path traversal exploitation techniques that align with CWE-434, which describes the insecure handling of file uploads. Attackers can exploit this by naming a PHP payload file with a .jpg extension, such as shell.jpg.php, and then leveraging the flawed path resolution to write the malicious code to a parent directory. This process typically involves uploading the file to a location like bl-kernel/ajax/ and then using the path traversal mechanism to write the payload to ../config/ or another directory where PHP code execution can occur. The vulnerability demonstrates a classic case of insufficient input validation and improper access control mechanisms that are commonly addressed by the principle of least privilege and proper file handling protocols.
The operational impact of this vulnerability is severe as it provides attackers with complete remote code execution capabilities on the affected web server. Once successfully exploited, adversaries can execute arbitrary commands, install backdoors, steal sensitive data, and potentially use the compromised system as a launch point for further attacks within the network. The vulnerability affects the integrity and confidentiality of the entire Bludit installation since the attacker gains the ability to manipulate the web application's behavior and access sensitive configuration files, user data, and potentially system-level resources. This type of vulnerability is particularly dangerous in environments where Bludit is used for content management, as it can lead to complete system compromise and data breaches.
Mitigation strategies for CVE-2019-16113 should focus on immediate patching of the Bludit application to version 3.9.3 or later, which contains the necessary fixes for the file upload validation and path traversal issues. Organizations should implement comprehensive file validation mechanisms that check both file extensions and content signatures rather than relying solely on extension-based filtering. The implementation of proper access controls and directory permissions can help contain the impact of any potential exploitation attempts. Security measures should include disabling unnecessary file upload capabilities, implementing strict file type validation, and deploying web application firewalls that can detect and block suspicious file upload patterns. This vulnerability is categorized under the MITRE ATT&CK framework as part of the T1190 - Exploit Public-Facing Application technique, and the remediation efforts should align with defensive strategies outlined in the framework for protecting against application-level exploitation.