CVE-2022-31041 in Open Forms
Summary
by MITRE • 06/13/2022
Open Forms is an application for creating and publishing smart forms. Open Forms supports file uploads as one of the form field types. These fields can be configured to allow only certain file extensions to be uploaded by end users (e.g. only PDF / Excel / ...). The input validation of uploaded files is insufficient in versions prior to 1.0.9 and 1.1.1. Users could alter or strip file extensions to bypass this validation. This results in files being uploaded to the server that are of a different file type than indicated by the file name extension. These files may be downloaded (manually or automatically) by staff and/or other applications for further processing. Malicious files can therefore find their way into internal/trusted networks. Versions 1.0.9 and 1.1.1 contain patches for this issue. As a workaround, an API gateway or intrusion detection solution in front of open-forms may be able to scan for and block malicious content before it reaches the Open Forms application.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/13/2022
CVE-2022-31041 represents a critical file validation vulnerability within the Open Forms application that undermines the security controls designed to restrict file uploads based on extension. This vulnerability exists in versions prior to 1.0.9 and 1.1.1, where the application fails to implement robust validation mechanisms for uploaded files. The flaw stems from insufficient input validation that allows malicious actors to manipulate file extensions through simple alteration or stripping techniques. This weakness directly violates the principle of least privilege and can be categorized under CWE-20, which addresses improper input validation. The vulnerability creates a path for attackers to bypass configured restrictions that should prevent the upload of potentially dangerous file types such as executable binaries or scripts, enabling them to upload malicious content disguised as legitimate files.
The operational impact of this vulnerability extends beyond simple file type manipulation and creates significant risks for organizations relying on Open Forms for data collection and processing. When users strip or alter file extensions, the application accepts files based on their actual content rather than their claimed type, potentially allowing malicious payloads to be silently uploaded to the server. This creates an attack surface where files with extensions like .pdf or .xls can actually contain executable code or other harmful content that bypasses the intended security controls. The vulnerability can be exploited through techniques aligned with ATT&CK tactic TA0005 (Defense Evasion) and TA0004 (Privilege Escalation) as attackers can use this to upload malicious files that may be processed by internal systems or downloaded by staff members. The risk is compounded by the fact that these files can be automatically processed by backend applications, creating a chain of potential compromise that extends beyond the initial upload point.
Organizations using vulnerable versions of Open Forms face substantial security risks including potential data breaches, system compromise, and lateral movement within their networks. The vulnerability essentially allows for a form of file type confusion attack where the application's trust model is undermined by accepting files that don't match their reported extensions. This creates opportunities for attackers to deliver malware through seemingly legitimate file uploads, potentially leading to full system compromise. The remediation approach requires immediate upgrading to versions 1.0.9 or 1.1.1 where proper validation mechanisms have been implemented. However, organizations should also implement additional protective measures such as API gateway filtering, intrusion detection systems, and content scanning solutions as recommended. These defensive measures align with the concept of defense in depth and provide additional layers of protection against similar vulnerabilities. The vulnerability also highlights the importance of implementing proper file validation at multiple points in the application lifecycle and demonstrates the necessity of validating file content rather than relying solely on extension-based restrictions. Organizations should consider implementing comprehensive file validation strategies that include MIME type checking, file signature verification, and content analysis to prevent similar issues from occurring in other applications.