CRITICAL
Source
Trivy
ID
AVD-AZU-0047

An inbound network security rule allows traffic from /0.

Network security rules should not use very broad subnets. Where possible, segments should be broken into smaller subnets.

Impact

Follow the appropriate remediation steps below to resolve the issue.

Set a more restrictive cidr range

1
2
3
4
5
 resource "azurerm_network_security_rule" "good_example" {
 	direction = "Inbound"
 	destination_address_prefix = "10.0.0.0/16"
 	access = "Allow"
 }
1
2
3
4
5
6
7
8
resource "azurerm_network_security_rule" "allow_lb_prober" {
  direction                                  = "Inbound"
  access                                     = "Allow"
  protocol                                   = "Tcp" # Probes are always TCP
  source_port_range                          = "*"
  destination_port_ranges                    = "443"
  source_address_prefix                      = "168.63.129.16" // single public IP (Azure well known)
}