CVE-2023-6887 in ForestBlog
Summary
by MITRE • 12/17/2023
A vulnerability classified as critical has been found in saysky ForestBlog up to 20220630. This affects an unknown part of the file /admin/upload/img of the component Image Upload Handler. The manipulation of the argument filename leads to unrestricted upload. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-248247.
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Analysis
by VulDB Data Team • 01/11/2024
This critical vulnerability exists in the saysky ForestBlog content management system version 20220630 and earlier, specifically within the administrative image upload functionality. The flaw resides in the file upload handler located at /admin/upload/img, where improper input validation allows attackers to bypass security restrictions. The vulnerability stems from inadequate sanitization of the filename parameter, which enables malicious users to upload arbitrary files without proper authorization or validation checks.
The technical implementation of this vulnerability demonstrates a classic unrestricted file upload flaw that can be categorized under CWE-434, which specifically addresses the scenario where applications allow file uploads without sufficient validation of file types, content, or naming conventions. This weakness creates a direct pathway for attackers to execute malicious code on the target system through the upload of potentially harmful files such as web shells, malicious scripts, or other exploit payloads. The vulnerability's remote exploitability means that attackers do not require physical access to the system or local network privileges to initiate the attack, making it particularly dangerous in publicly accessible environments.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, as it provides attackers with potential persistent access to the compromised system. According to ATT&CK framework categorization, this vulnerability maps to T1190 (Exploit Public-Facing Application) and T1059 (Command and Scripting Interpreter) as attackers can leverage the uploaded files to establish backdoors, execute commands, and maintain long-term access to the affected server. The public disclosure of the exploit further amplifies the risk, as it eliminates the need for sophisticated attack development and provides readily available tools for exploitation. Organizations running affected versions of ForestBlog face significant exposure to data breaches, system compromise, and potential lateral movement within their network infrastructure.
Mitigation strategies should prioritize immediate patching of the affected software to address the core validation flaw in the image upload handler. Additionally, implementing strict file type validation, content inspection, and secure file storage practices can help prevent exploitation attempts. Network segmentation and monitoring of upload activities should be enhanced to detect suspicious file upload patterns. Organizations should also consider implementing web application firewalls and access controls to restrict administrative upload functionality to trusted sources only. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other components of the application stack, as this vulnerability demonstrates a pattern of insufficient input validation that may exist elsewhere in the system architecture.