CVE-2025-23918 in Smallerik File Browser Plugin
Summary
by MITRE • 01/22/2025
Unrestricted Upload of File with Dangerous Type vulnerability in NotFound Smallerik File Browser allows Upload a Web Shell to a Web Server. This issue affects Smallerik File Browser: from n/a through 1.1.
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Analysis
by VulDB Data Team • 01/22/2025
The CVE-2025-23918 vulnerability represents a critical security flaw in the NotFound Smallerik File Browser software that enables unauthorized remote code execution through malicious file uploads. This vulnerability stems from inadequate input validation and sanitization mechanisms within the file upload functionality, allowing attackers to bypass security restrictions and deploy web shells on affected systems. The flaw exists in versions ranging from the initial release through version 1.1, indicating a persistent issue that has not been adequately addressed in the software lifecycle.
The technical implementation of this vulnerability resides in the application's file handling processes where it fails to properly validate file extensions, MIME types, or file content before storing uploaded files on the web server. This unrestricted upload capability creates a pathway for attackers to execute arbitrary code by uploading malicious files that can be interpreted as web scripts by the server. The vulnerability directly maps to CWE-434, which specifically addresses the insecure upload of file types that can be executed by the web server, making it a prime target for exploitation in web application attacks.
From an operational perspective, this vulnerability poses severe risks to organizations relying on the Smallerik File Browser for file management operations. An attacker who successfully exploits this flaw can gain persistent access to the web server, potentially leading to complete system compromise, data exfiltration, and lateral movement within the network. The impact extends beyond immediate code execution as the deployed web shell can be used to maintain access, escalate privileges, and establish command and control channels. This vulnerability aligns with ATT&CK technique T1190, which covers exploiting vulnerabilities in web applications to gain initial access to target systems.
Mitigation strategies should include immediate implementation of file type restrictions, content validation, and proper sanitization of all uploaded files. Organizations should deploy web application firewalls to monitor and block suspicious upload attempts, implement strict file extension filtering, and ensure that uploaded files are stored outside the web root directory. Additionally, regular security updates and patches should be applied to the Smallerik File Browser software, while network segmentation and access controls should be enforced to limit potential damage from successful exploitation attempts. The vulnerability demonstrates the critical importance of input validation and secure file handling practices in web applications, emphasizing the need for comprehensive security testing and continuous monitoring of application components.