Safely Storing Sensitive Documents in the Cloud
Introduction
Storing sensitive documents in the cloud has become increasingly common as more businesses adopt cloud-based services. However, it also introduces risks around data privacy and security that must be properly addressed. In this article, I will provide an in-depth look at how to safely store sensitive documents in the cloud.
Evaluating Cloud Storage Providers
Security practices
When evaluating cloud storage providers, it’s critical to understand their security practices. Look for providers that encrypt data both in transit and at rest, use strong encryption protocols like AES-256, and allow you to manage your own encryption keys. Multifactor authentication, rigorous third-party audits, and SOC 2 compliance are also good signs.
Geographic location
Pay attention to where your data will be stored. Some regions like the EU have strong data privacy laws. Avoid providers that can’t commit to keeping your data in a specific geographic area.
Access controls
You should be able to restrict access to sensitive data through permissions, authentication, and encryption. Look for sophisticated tools to control who can view, edit, share, and delete documents.
Anomaly detection
Leading providers use AI and machine learning to detect suspicious activity. These capabilities can spot potential breaches and cyber threats faster.
Securing Documents Before Upload
Classify sensitivity
Not all documents have equal sensitivity. Classify documents so you can tailor security for each category. Highly sensitive documents deserve the strongest protection.
Encrypt locally
Encrypt documents locally before uploading to the cloud. This ensures they remain encrypted if there’s a breach. Use strong encryption like AES-256.
Redact info
Scrub documents of unnecessary sensitive details like social security numbers before uploading them to the cloud. This reduces exposure.
Watermark documents
Watermarking documents with user IDs makes them traceable in case of unauthorized sharing or leaks.
Limit metadata
Remove metadata like author name and GPS coordinates from files before upload. Metadata can reveal sensitive information.
Managing Access Controls
No public sharing
Never make sensitive documents publicly accessible or sharable via public links. Only authorized users should have access.
Access tiers
Use access tiers like view-only, can edit, and can edit + share to give users only the permissions they need.
Time limits
Set time limits on document access for temporary employees or contractors. Access automatically expires when no longer needed.
Regular audits
Audit user access and document permissions regularly to detect overexposure. Remove access that is no longer necessary.
MFA for sharing
Require multifactor authentication to share documents externally. This prevents unauthorized sharing by compromised accounts.
Backing Up and Recovering Data
Versioning
Use a cloud provider with built-in versioning. You can recover from malicious encryption or deletion by reverting to an earlier, uncorrupted version.
Download backups
Periodically download encrypted backup copies of critical documents and store them offline. This guards against catastrophic loss.
Mirror backups
Maintain copies of sensitive cloud documents in another secured location. This provides an alternate recovery source.
Test recovery
Verify you can actually restore documents from backups. Recovery procedures may have flaws that only get detected during a test.
Backup alerts
Use tools that alert you if a certain time passes without a successful backup. A lapsed backup could mean recovery trouble.
Monitoring for Threats
Access alerts
Get notified of suspicious activities like abnormal spikes in data access or logins from new locations/devices.
Auto-scanning
Use a provider that automatically scans documents for malware, viruses, or ransomware. This detects threats early.
Change alerts
Alerts for unexpected changes to permissions, encryption keys, user access, or sharing settings help detect malicious tampering.
SIEM integration
Send logs from your cloud apps and services into a SIEM for advanced monitoring and threat correlation.
Outside perspectives
Hire third-party security firms to manually review your configuration and test it for weaknesses. They provide fresh perspective.
Conclusion
Storing sensitive documents in the cloud has risks, but with proper precautions it can be done safely. Evaluate providers thoroughly, control access tightly, encrypt locally, back up redundantly, and monitor continuously. With the right cloud provider, security controls, and monitoring, you can reduce risk and confidently move sensitive data to the cloud.
