How Azure SAS Expiration Actions Empower Customer
🔐 Locking Down Access, Unlocking Trust
“Our data perimeter was solid… until that token kept the backdoor open.”
That’s what Rahul, a cloud security lead at a multinational bank, muttered after a routine access audit uncovered an anomaly: a shared access signature (SAS) token still functioning days after its intended expiration. The storage policy said 24 hours — but someone had extended it manually. It didn’t cause a breach — but it could have.
As financial institutions digitize, the stakes around access control only grow. Tokens are convenient. But convenience, unchecked, breeds risk. That’s where Microsoft’s latest enhancement to Azure Storage SAS Expiration Policy enters the spotlight — with a new layer of enforcement that’s not just smart but strict when needed.
What’s New?
SAS Expiration Policy Gets Teeth, Shared Access Signatures (SAS) have long been the go-to for delegating access to storage objects in Azure, Its lightweight, flexible, but prone to misuse if not tightly governed.
With this update, Azure now supports SAS Expiration Actions:
- Log: Audit any token use that violates the defined expiration interval. Track, trend, investigate.
- Block: Enforce the policy. Out-of-policy tokens are denied. Period.
No more silent overrides via signed expiry fields. The administrator’s policy now actually means something.
A Financial Industry Use Case: “Audit First, Enforce Next”
Let’s go back to Rahul’s bank.
His team had built a secure file-sharing portal for onboarding institutional clients. Client documents — KYC forms, contracts, audit trails — were stored on Azure Blob Storage. External relationship managers got access via SAS tokens, typically valid for 48 hours.
In practice, tokens were being generated ad hoc. Some expired as planned. Others were modified — valid for a week, sometimes longer. The bank had a policy. But Azure didn’t enforce it… until now.
The Shift:
Phase 1 — Log Mode: The bank enabled SAS Expiration Action in Log mode. They monitored violations via Azure Monitor and Sentinel for two weeks, identifying teams and apps that extended SAS validity.
Phase 2 — Partner Engagement: Microsoft service partners stepped in to:
- Conduct token lifecycle audits.
- Map token usage to business processes.
- Redesign the storage access architecture using short-lived SAS tokens and Azure Managed Identities where possible.
Phase 3 — Block Mode: Once confidence was high, the bank switched to Block mode. No more out-of-policy SAS tokens allowed. Compliance was codified.
Where Partners Make Money
This new feature isn’t just a toggle switch — it’s a governance opportunity. Here’s how Microsoft service partners can build revenue streams:
1. Access Control Assessment Workshops
Offer security workshops to audit SAS token usage across the enterprise. Identify rogue practices and build a maturity roadmap.
2. Implementation Services
Help configure SAS Expiration Policies via ARM, Bicep, or Azure CLI at scale. Integrate with existing CI/CD and IaC frameworks.
3. Monitoring and Analytics
Set up diagnostic logs, integrate with Azure Monitor and Microsoft Sentinel, and create visual dashboards that help clients understand token trends, violations, and remediations.
4. Policy Enforcement Governance
Deliver Change Management and Policy-as-Code templates that ensure compliance is enforced not just on paper — but in practice.
5. Modernization Projects
Help migrate from legacy SAS access to more secure models like Azure AD authentication, OAuth, or Managed Identities.
My Thoughts
In the high-stakes world of finance, intent isn’t enough — enforcement is everything. Azure’s SAS Expiration Actions give firms the power to do more than hope policies are followed — they can verify, audit, and block when needed.
And for Microsoft partners, this is not just another security update — it’s an invitation to embed governance into storage, educate clients, and drive transformation.
Rahul’s team sleeps easier now. Not because threats are gone — but because token access finally has boundaries that mean business.
🧑💻 About the Author
Vijay Borkar is a Microsoft Partner’s — Cloud Solution Architect helping Microsoft partners scale faster and smarter across Singapore and ASIA using Azure. he specializes in simplifying architecture for cross-region deployments and empowering partners through co-sell ready services. Follow me on Medium and connect me LinkedIn here: (22) Vijay Borkar | LinkedIn
