Azure Networking - Ensure RDP Access is Restricted from the Internet

Overview

Disable RDP access on network security groups from the Internet.

Why:

The potential security problem with using RDP over the Internet is that attackers can use various brute force techniques to gain access to Azure Virtual Machines. Once the attackers gain access, they can use a virtual machine as a launch point for compromising other machines on an Azure Virtual Network or even attack networked devices outside of Azure.

Audit

From Azure Command Line (CLI)

az network nsg list --query [*].[name,securityRules]

Ensure none of the following appears

"access" : "Allow"
"destinationPortRange" : "3389" or "*" or "[port range containing 3389]" "direction" : "Inbound"
"protocol" : "TCP"
"sourceAddressPrefix" : "*" or "0.0.0.0" or "<nw>/0" or "/0" or "internet" or "any"

Fix:

Disable direct RDP access to your Azure Virtual Machines from the Internet. After direct RDP access from the Internet is disabled, you have other options you can use to access these virtual machines for remote management:

References:

• https://docs.microsoft.com/en-us/azure/security/azure-security-network-security-best-practices%23disable-rdpssh-access-to-azure-virtual-machines