CVE-2025-28168 in Multiple File Upload
Summary
by MITRE • 05/05/2025
Outsystems Multiple File Upload < 3.1.0 is vulnerable to Unrestricted File Upload. The vulnerability is because file extension and size validations are enforced solely on the client side. An attacker can intercept the upload request and modify the parameter to bypass extension restrictions and upload arbitrary files.
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Analysis
by VulDB Data Team • 10/01/2025
The vulnerability identified as CVE-2025-28168 affects Outsystems Multiple File Upload versions prior to 3.1.0 and represents a critical security flaw categorized under CWE-434 Unrestricted Upload of File. This vulnerability stems from a fundamental architectural weakness where file validation controls are implemented exclusively on the client-side rather than maintaining robust server-side validation mechanisms. The flaw creates a dangerous scenario where attackers can circumvent security measures by intercepting and modifying upload requests, effectively bypassing the intended file type restrictions that are designed to prevent malicious file uploads.
The technical implementation of this vulnerability exploits the lack of proper server-side validation controls within the file upload functionality. When users attempt to upload files through the Outsystems platform, the system relies entirely on client-side JavaScript validation to check file extensions and sizes. This approach is fundamentally flawed because client-side validation can be easily bypassed through various means including request interception, modification, or direct API calls. Attackers can utilize tools such as burp suite or curl to modify the upload parameters, changing file extensions to bypass validation checks and upload malicious files such as web shells or executable binaries that would otherwise be rejected by proper server-side validation.
The operational impact of this vulnerability is severe and far-reaching within the context of web application security. An attacker who successfully exploits this vulnerability can upload arbitrary files to the target system, potentially leading to remote code execution, data compromise, or complete system takeover. The vulnerability enables attackers to deploy malicious payloads such as php shells, aspx backdoors, or other executable files that can be executed within the web application context. This creates a persistent threat vector that can be exploited for ongoing unauthorized access, data exfiltration, or lateral movement within the compromised network environment. The risk is amplified because the vulnerability affects the core file upload functionality of the platform, making it a prime target for exploitation.
Security professionals should consider this vulnerability in relation to the broader ATT&CK framework, particularly under the techniques T1190 Exploit Public-Facing Application and T1059 Command and Scripting Interpreter. The vulnerability directly enables adversaries to establish persistent access through malicious file uploads, while also potentially facilitating privilege escalation and lateral movement within the target environment. Organizations should implement comprehensive mitigations including immediate patching to version 3.1.0 or later, implementing robust server-side file validation controls, and conducting thorough security assessments of all file upload functionalities. Additional protective measures should include restricting file upload capabilities to authenticated users only, implementing strict file type whitelisting, and deploying web application firewalls with content inspection capabilities to detect and prevent malicious upload attempts. The vulnerability also highlights the importance of defense in depth strategies, where client-side validations should never be considered the sole line of defense against security threats, as demonstrated by the principles outlined in the OWASP Top Ten and the NIST Cybersecurity Framework.