CVE-2022-31041 is a security vulnerability affecting the Open Forms application, a platform used for creating and publishing smart forms that support file uploads. The vulnerability arises from improper input validation (CWE-20) and unrestricted file upload of potentially dangerous file types (CWE-434). Specifically, in versions prior to 1.0.9 and between 1.1.0-rc0 and 1.1.1, Open Forms allows end users to upload files with extensions restricted by configuration (e.g., only PDF or Excel files) to bypass these restrictions by altering or stripping the file extensions. This means that malicious files, potentially containing malware or scripts, can be uploaded to the server despite the intended file type restrictions. Once uploaded, these files may be accessed or downloaded by staff or other internal applications for processing, thereby introducing a risk of malicious content entering trusted internal networks. The vulnerability is mitigated in versions 1.0.9 and 1.1.1, which include patches to enforce stricter validation of uploaded file types. As an interim measure, deploying an API gateway or intrusion detection system (IDS) in front of the Open Forms application can help scan and block malicious content before it reaches the vulnerable application. There are no known exploits in the wild at this time, but the vulnerability poses a risk of malware infiltration, data compromise, or further exploitation within internal systems due to insufficient file validation controls.

For European organizations using Open Forms, this vulnerability could lead to significant security risks. Malicious actors could exploit the improper input validation to upload harmful files disguised as benign documents, potentially leading to malware infections, ransomware deployment, or unauthorized access within internal networks. This could compromise confidentiality by exposing sensitive data, integrity by altering or corrupting data, and availability by disrupting services through malware or denial-of-service conditions. Organizations in sectors such as government, healthcare, finance, and critical infrastructure, which often rely on form-based data collection and processing, may be particularly vulnerable. The risk is amplified if uploaded files are automatically processed or integrated into workflows without additional scanning, increasing the likelihood of internal compromise. Given the potential for lateral movement within networks after initial compromise, the vulnerability could facilitate broader attacks against European enterprises, impacting operational continuity and regulatory compliance, especially under GDPR requirements for data protection.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately upgrade Open Forms to versions 1.0.9 or 1.1.1 or later, which contain the necessary patches to enforce proper file extension validation. 2) Implement robust file scanning solutions at the perimeter, such as an API gateway or IDS/IPS, configured to inspect uploaded files for malicious content, including signature-based and heuristic malware detection. 3) Enforce strict content-type validation on the server side, not relying solely on file extensions, by inspecting file headers (magic bytes) to confirm file types before processing or storing them. 4) Limit the privileges of the Open Forms application and its file storage directories to minimize the impact of any malicious file execution. 5) Establish monitoring and alerting for unusual file upload patterns or access to uploaded files to detect potential exploitation attempts early. 6) Educate staff on the risks of opening files from untrusted sources, especially those uploaded via forms, and encourage cautious handling of downloaded files. 7) Review and harden downstream systems that process uploaded files to ensure they perform their own validation and scanning. These targeted measures go beyond generic advice by focusing on layered defenses, validation at multiple points, and operational awareness tailored to the nature of this vulnerability.