Establishing strong monitoring and reporting over your encryption operations is a crucial security control. By keeping a close eye on your cryptographic policies, processes, and procedures, you can quickly identify and respond to any potential issues or deviations. This allows you to maintain the confidentiality and integrity of your sensitive data.

Where did this come from?

This control comes from the CSA Cloud Controls Matrix v4.0.10 - 2023-09-26. You can download the full matrix with additional details from https://cloudsecurityalliance.org/artifacts/cloud-controls-matrix-v4. The Cloud Security Alliance develops this matrix as a set of best practices for securing cloud environments. For more background, check out their Overview and Methodology.

Who should care?

• Security engineers responsible for designing encryption systems
• DevOps teams deploying and operating encryption in production
• Compliance officers ensuring cryptography meets regulatory requirements
• Auditors assessing the effectiveness of encryption controls

What is the risk?

Poor monitoring of encryption operations can lead to several adverse events:

• Undetected misconfigurations or failures in encryption resulting in exposure of sensitive data
• Unauthorized changes to encryption policies or procedures weakening security posture
• Encryption keys being accessed or used improperly without timely detection
• Inability to prove compliance with encryption-related regulatory requirements

Proactive monitoring and reporting can help prevent, quickly detect, and effectively respond to these risks. The extent of risk reduction depends on the comprehensiveness and timeliness of the monitoring.

What's the care factor?

For organizations handling sensitive data, especially those in regulated industries, the care factor for this control should be high. Encryption is a key safeguard for data confidentiality. Any gaps in its implementation can undermine the whole effort.

Even a small lapse in encryption ops can lead to a major data breach with severe financial and reputational consequences. Investing in robust monitoring is well worth it compared to those costs.

When is it relevant?

This control is relevant whenever you use encryption to protect data, which these days is most of the time, especially in the cloud. Some key use cases:

• Encrypting data at-rest in storage (e.g. databases, S3 buckets, EBS volumes)
• Encrypting data in-transit over the network (e.g. HTTPS, VPN, AWS PrivateLink)
• Securing sensitive app configs/secrets (e.g. in AWS Secrets Manager or HashiCorp Vault)

It may be less critical for use cases with less sensitive data or lower compliance requirements. But in general, if you've gone to the effort of encrypting, you should monitor it.

What are the trade-offs?

Implementing comprehensive encryption monitoring does come with some costs:

• Increased complexity in logging pipelines to capture and centralize relevant events
• Development effort to establish reporting and alerting on encryption health metrics
• Potentially larger log storage and analysis costs due to extra verbosity
• Some performance overhead from things like file integrity monitoring on logs

But for most organizations, these are manageable trade-offs compared to the risk reduction benefits. And many monitoring tools have built-in support for tracking encryption.

How to make it happen?

Here's a high-level plan for implementing encryption monitoring and reporting:

1. Identify all systems/components performing encryption and managing keys. Common ones:
   • App servers/containers
   • Load balancers terminating TLS
   • Databases and storage services
   • Secrets managers and key vaults
2. Configure each component to log encryption-related events at an appropriate level. Capture details like:
   • Requests to access/use keys (success and failure)
   • Changes to encryption config (e.g. cipher suites, key rotation frequency)
   • Performance of crypto operations
   • Errors and exceptions
3. Use file integrity monitoring (FIM) or similar on the generated log files to detect tampering.
4. Aggregate encryption logs to a central location like a SIEM or log analysis tool. AWS CloudTrail plus CloudWatch is a common stack.
5. Establish reports and dashboards to track key metrics over encryption health, such as:
   • Percentage of systems/data volumes encrypted
   • Key rotation frequency vs. policy
   • Anomalous behavior like spikes in key access failures
6. Configure alerts to trigger on signs of possible issues like decryption failures or unauthorized encryption config changes.
7. Document the expected encryption ops procedures and use the monitoring to detect and handle deviations.
8. Perform regular audits and testing to validate monitoring effectiveness and adherence to policy.

What are some gotchas?

A few things to watch out for when setting this up:

• Ensure you have necessary permissions to enable detailed logging on encryption components. For example:
  • kms:GetKeyRotationStatus to check KMS key rotation
  • CloudTrail permissions to access encryption event history
• Avoid logging sensitive data like encryption keys or PII. Use secure key references instead.
• FIM tools may need to be tuned to avoid excessive alerts on expected log file changes.
• Encryption monitoring can produce a high volume of events. Use smart filtering and analysis to avoid overload.
• Monitoring detects but doesn't prevent. Be sure to have response playbooks for handling encryption incidents.

What are the alternatives?

While there's no direct substitute for encryption monitoring, a few practices can complement it:

• Penetration testing to proactively find encryption weaknesses
• Auditing and alerting on changes to encryption-related resource configs (e.g. with AWS Config Rules)
• Following hardening guides like CIS Benchmarks to ensure secure encryption config
• Regular key rotation and re-encryption to limit blast radius of any leaks

But these are not replacements for monitoring the actual running state of encryption.

Explore further

For more details and guidance, check out:

• AWS Encrypting Data at Rest Whitepaper
• Azure Key Vault Logging
• GCP Monitoring Cloud KMS
• CIS Controls v8 3.11: Encrypt Sensitive Data at Rest
• NIST SP 800-57 Pt. 2 Cryptographic Key Management

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