Control: Azure > CIS v3.0 > 05 - Database Services > 05.01 - Azure SQL Database > 05.01.02 - Ensure no Azure SQL Databases allow ingress from 0.0.0.0/0 (ANY IP)

Configures auditing against a CIS Benchmark item.

Level: 1

Ensure that no SQL Databases allow ingress from 0.0.0.0/0 (ANY IP).

Azure SQL Server includes a firewall to block access to unauthorized connections. More granular IP addresses can be defined by referencing the range of addresses available from specific datacenters.

By default, for a SQL server, a Firewall exists with StartIp of 0.0.0.0 and EndIP of 0.0.0.0 allowing access to all the Azure services.

Additionally, a custom rule can be set up with StartIp of 0.0.0.0 and EndIP of 255.255.255.255 allowing access from ANY IP over the Internet.

In order to reduce the potential attack surface for a SQL server, firewall rules should be defined with more granular IP addresses by referencing the range of addresses available from specific datacenters.

If Allow Azure services and resources to access this server is 'Checked', this will allow resources outside of the subscription/tenant/organization boundary, within any region of Azure, to effectively bypass the defined SQL Server Network ACL on public endpoint. A malicious attacker can successfully launch a SQL server password bruteforce attack by creating a virtual machine in any Azure subscription/region, from outside of the subscription boundary where the SQL Server is residing