Introduction to Azure Defender for Storage

Azure Defender for Storage is an Azure-native layer of security intelligence that detects unusual and potentially harmful attempts to access or exploit your storage accounts. It utilizes the advanced capabilities of security AI and Microsoft Threat Intelligence to provide contextual security alerts and recommendations.

Security alerts are triggered when anomalies in activity occur. These alerts are integrated with Azure Security Center, and are also sent via email to subscription administrators, with details of suspicious activity and recommendations on how to investigate and remediate threats.

Availability

Aspect Details
Release state: General Availability (GA)
Pricing: Azure Defender for Storage is billed as shown on Security Center pricing
Protected storage types: Blob Storage
Azure Files
Azure Data Lake Storage Gen2
Clouds: Yes Commercial clouds
Yes US Gov
No China Gov, Other Gov

What are the benefits of Azure Defender for Storage?

Azure Defender for Storage provides:

  • Azure-native security - With 1-click enablement, Defender for Storage protects data stored in Azure Blob, Azure Files, and Data Lakes. As an Azure-native service, Defender for Storage provides centralized security across all data assets managed by Azure and is integrated with other Azure security services such as Azure Sentinel.
  • Rich detection suite - Powered by Microsoft Threat Intelligence, the detections in Defender for Storage cover the top storage threats such as anonymous access, compromised credentials, social engineering, privilege abuse, and malicious content.
  • Response at scale - Security Center's automation tools make it easier to prevent and respond to identified threats. Learn more in Automate responses to Security Center triggers.

High-level overview of the features of Azure Defender for Storage

What kind of alerts does Azure Defender for Storage provide?

Security alerts are triggered when there's:

  • Suspicious access patterns - such as successful access from a Tor exit node or from an IP considered suspicious by Microsoft Threat Intelligence
  • Suspicious activities - such as anomalous data extraction or unusual change of access permissions
  • Upload of malicious content - such as potential malware files (based on hash reputation analysis) or hosting of phishing content

Alerts include details of the incident that triggered them, as well as recommendations on how to investigate and remediate threats. Alerts can be exported to Azure Sentinel or any other third-party SIEM or any other external tool.

Tip

It's a best practice to configure Azure Defender for Storage on the subscription level, but you may also configure it on individual storage accounts.

What is hash reputation analysis for malware?

To determine whether an uploaded file is suspicious, Azure Defender for Storage uses hash reputation analysis supported by Microsoft Threat Intelligence. The threat protection tools don’t scan the uploaded files, rather they examine the storage logs and compare the hashes of newly uploaded files with those of known viruses, trojans, spyware, and ransomware.

When a file is suspected to contain malware, Security Center displays an alert and can optionally email the storage owner for approval to delete the suspicious file. To set up this automatic removal of files that hash reputation analysis indicates contain malware, deploy a workflow automation to trigger on alerts that contain "Potential malware uploaded to a storage account”.

Note

To enable Security Center's threat protection capabilities, you must enable Azure Defender on the subscription containing the applicable workloads.

You can enable Azure Defender for Storage at either the subscription level or resource level.

Trigger a test alert for Azure Defender for Storage

To test the security alerts from Azure Defender for Storage in your environment, generate the alert "Access from a Tor exit node to a storage account" with the following steps:

  1. Open a storage account with Azure Defender for Storage enabled.

  2. From the sidebar, select “Containers” and open an existing container or create a new one.

    Opening a blob container from an Azure Storage account

  3. Upload a file to that container.

    Caution

    Don't upload a file containing sensitive data.

  4. Use the context menu on the uploaded file to select “Generate SAS”.

    The generate SAS option for a file in a blob container

  5. Leave the default options and select Generate SAS token and URL.

  6. Copy the generated SAS URL.

  7. On your local machine, open the Tor browser.

    Tip

    You can download Tor from the Tor Project site https://www.torproject.org/download/.

  8. In the Tor browser, navigate to the SAS URL.

  9. Download the file you uploaded in step 3.

    Within two hours you'll get the following security alert from Security Center:

    Security alert regarding access from a Tor exit node

Next steps

In this article, you learned about Azure Defender for Storage.

For related material, see the following articles: