Control: 7.3 Ensure that UDP access from the Internet is evaluated and restricted
Description
Network security groups should be periodically evaluated for port misconfigurations. Where certain ports and protocols may be exposed to the Internet, they should be evaluated for necessity and restricted wherever they are not explicitly required.
The potential security problem with broadly exposing UDP services over the Internet is that attackers can use DDoS amplification techniques to reflect spoofed UDP traffic from Azure Virtual Machines. The most common types of these attacks use exposed DNS, NTP, SSDP, SNMP, CLDAP and other UDP-based services as amplification sources for disrupting services of other machines on the Azure Virtual Network or even attack networked devices outside of Azure.
Remediation
Where UDP is not explicitly required and narrowly configured for resources attached to the Network Security Group, Internet-level access to your Azure resources should be restricted or eliminated.
For internal access to relevant resources, configure an encrypted network tunnel such as:
Default Value
By default, UDP access from internet is not enabled.
Usage
Run the control in your terminal:
powerpipe control run azure_compliance.control.cis_v300_7_3Snapshot and share results via Turbot Pipes:
powerpipe loginpowerpipe control run azure_compliance.control.cis_v300_7_3 --shareSQL
This control uses a named query:
network_security_group_udp_service_restricted