Hello Folks,
In this article, we will walk through a very serious problem that I have seen in multiple Azure environments in my customers: an Azure environment where outbound firewall rules allowed access to any Azure Storage account on the internet.

On the surface, the rule looked safe enough: outbound access was limited to Azure Storage endpoints. In reality, this meant that any storage account in any tenant was reachable, as long as it lived behind a standard *.blob.core.windows.net or *.dfs.core.windows.net style FQDN. From a data exfiltration perspective, this is a big red flag. Any workload that can send HTTPS traffic to arbitrary storage accounts can quietly move data out of your tenant, and that traffic is almost indistinguishable from normal storage operations.



