12 Secure File Upload Best Practices
Here are some best practices to ensure your file uploads are safe and secure.
1. Authenticate users
This is essential for protecting data privacy and preventing identity theft. You should implement, at minimum, two-factor authentication (2FA), which requires two types of authentication (for example, a login password and a code sent by text). For increased security, use multi-factor authentication (MFA), which typically requires at least three types of authentication.
2. Implement access and download controls
Restrict who can download specific files based on their role and permissions to prevent sensitive data from getting into the wrong hands. For example, you can make it so that only people in management can access uploaded files. Types of access control include mandatory access control (MAC), discretionary access control (DAC), role-based access control (RBAC), rule-based access control, and attribute-based access control (ABAC).
3. Conduct regular security audits
Conduct regular security audits on your system to identify and fix vulnerabilities in the file upload process. If you use third-party software for file transfer, ensure they do this as well. This includes documentation review to ensure compliance, access controls review, security controls evaluation, and more. These audits can be paired with third-party penetration testing.
4. Ensure compliance with data protection regulations
Verify that your systems, processes, and vendors are compliant with data privacy and data management regulations such as GDPR and SOC 2. Not only does this protect your organization from legal repercussions, but it also helps inspire trust in customers as big data leaks and breaches continue to make the news.
5. Provide ongoing employee training on secure file handling
Even if you have all the right technology and processes in place, if your users aren’t educated about secure file uploading practices, your systems can be vulnerable to attacks. Make sure everyone in your organization undergoes regular security awareness training about how to properly safeguard data, avoid downloading malware, and set up strong passwords.
6. Implement file type restrictions
Limit uploads only to necessary file types to minimize the chances of harmful content being uploaded to your servers. For example, attackers can try to inject malware into your system using executable files with extensions like .exe, .dll, .bat, or .sh. Restricting users from uploading those file types can help keep your uploads secure. Having a file upload portal that allows you to restrict file types with just a couple of clicks can be a big help.
7. Store files in secure cloud storage
Choose a cloud storage provider that meets your criteria for speed, simplicity, reliability, cost, and of course, security. It should have strong security features such as data encryption (in transit and at rest), user authentication tools, access controls, vulnerability scans, and activity logs/audit trails. Integrating your file transfer solution with cloud storage to automate content uploads or downloads can also improve security, since it reduces the chance of a manual error sneaking into the file transfer process.
8. Encrypt your files
Data encryption converts messages or files into unreadable code through algorithms that scramble the data. If your files somehow get into the wrong hands, the data will be hidden by a string of complex characters. Make sure to use strong encryption, such as AES-256 and TLS 1.2, on data in flight and at rest.
9. Scan files for malware
Before uploading files, scan them for trojans, viruses, or other malware using tools like antivirus software, command line interfaces (CLIs), or software development kits (SDKs). Make sure to regularly update the software to protect yourself from emerging threats. If you use a file transfer service, ensure it performs regular malware scanning on all file transfers.
10. Update and patch software
Performing these updates ensures that your software runs on its latest version, which helps optimize performance and fixes known security flaws. Consider that self-hosted file transfer solutions can make your system more vulnerable than the cloud in this regard, because you have to make these updates yourself (a process that’s often delayed or forgotten about when performed manually). Cloud users, on the other hand, can count on their providers to make updates quickly and automatically.
11. Record activity logs and audit trails
Keep track of who’s uploading and downloading files and accessing your software systems, as well as when these events take place. These records allow you to monitor your systems for suspicious activity and unauthorized access. If you use a file sharing service, ensure it includes a centralized admin console to track usage all in one place to stay organized and allow for auditing, if necessary.
12. Sanitize file names
Don’t put sensitive data or information into file names (e.g. addresses, account numbers, full names). Creating a file naming convention that everyone follows could help with this as well as staying organized. For uploaded files that don’t follow your naming conventions, you can rename them to prevent attackers from injecting malicious code or scripts into a file name. Remove potentially dangerous characters or patterns.
Any file sharing service you use should allow you to set file naming conventions in its file uploader, so collaborators have no choice but to follow your file name rules.
