Back to Glossary

Glossary Term

Azure Blob Storage

Microsoft’s object storage service for unstructured data; improper sharing or leaked SAS tokens can expose entire containers.

1 min read

Share this definition

Post it to your feed or send it to teammates.

What it is

Azure Blob Storage is Microsoft’s cloud-based object storage service for unstructured data such as images, backups, and analytics workloads. Data lives inside containers, which function similarly to Amazon S3 buckets. Azure offers tiered storage classes—Hot, Cool, and Archive—to balance performance and cost. Access is governed by Azure Active Directory (Azure AD), shared access signatures (SAS), and container-level permissions. Encryption at rest is enabled by default using Microsoft-managed keys or customer-managed keys from Azure Key Vault, and transport is secured with HTTPS/TLS.

Security features include Microsoft Defender for Storage for anomaly detection, lifecycle management policies for automated retention, immutable blob storage, and integration with Azure Monitor and Log Analytics. However, misconfigurations—especially anonymous public access to containers—have historically exposed sensitive data. SAS tokens embedded in code or shared broadly can also bypass intended authentication boundaries.

Why it matters

Blob Storage often houses critical backups, logs, and customer data. Publicly accessible containers or leaked SAS tokens allow attackers to list and download blob contents. Because organizations frequently replicate production data for analytics or disaster recovery, exposure of Blob Storage can cascade into major breaches. Even temporary misconfigurations may result in data being indexed or archived by third parties.

How to reduce risk

  • Disable anonymous public access at the storage account and container levels.
  • Favor Azure AD-based access control over SAS tokens whenever possible.
  • If SAS tokens are required, limit their permissions and lifetimes, and monitor for leakage.
  • Enable Microsoft Defender for Storage to detect unusual access patterns and malware uploads.
  • Require encryption with customer-managed keys for sensitive workloads.
  • Use Azure Policy and Defender for Cloud recommendations to enforce compliance.
  • Audit access logs with Azure Monitor and Log Analytics to detect suspicious behavior.