Sensitive Port Is Exposed To Wide Private Network

• Query id: c6c7b33d-d7f6-4ab8-8c82-ca0431ecdb7e
• Query name: Sensitive Port Is Exposed To Wide Private Network
• Platform: Terraform
• Severity: Medium
• Category: Networking and Firewall
• URL: Github

Description

A sensitive port, such as port 23 or port 110, is open for wide private network in either TCP or UDP protocol
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "azurerm_network_security_rule" "positive1" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "UDP"
     source_port_range           = "*"
     destination_port_range      = "61621"
     source_address_prefix       = "172.16.0.0/12"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive2" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23-34"
     source_address_prefix       = "172.16.0.0/12"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive3" {
     name                        = "example"
     priority                      = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "21-23"
     source_address_prefix       = "172.16.0.0/12"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive4" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "192.168.0.0/16"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive5" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "UDP"
     source_port_range           = "*"
     destination_port_range      = "23,245"
     source_address_prefix       = "192.168.0.0/16"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive6" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "192.168.0.0/16"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive7" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "UDP"
     source_port_range           = "*"
     destination_port_range      = "22-64, 94"
     source_address_prefix       = "10.0.0.0/8"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive8" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "14, 23, 48"
     source_address_prefix       = "10.0.0.0/8"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive9" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "12, 23-24,46"
     source_address_prefix       = "10.0.0.0/8"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "positive10" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "46-146, 18-36, 1-2, 3"
     source_address_prefix       = "10.0.0.0/8"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "azurerm_network_security_rule" "negative1" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Deny"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "*"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative2" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "Icmp"
     source_port_range           = "*"
     destination_port_range      = "23-34"
     source_address_prefix       = "*"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative3" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "8-174"
     source_address_prefix       = "0.0.0.0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative4" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23-196"
     source_address_prefix       = "0.0.0.0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative5" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "/1"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative6" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "43"
     source_address_prefix       = "/0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative7" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "Icmp"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "internet"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative8" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "*"
     source_port_range           = "*"
     destination_port_range      = "22, 24,49-67"
     source_address_prefix       = "any"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative9" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "Icmp"
     source_port_range           = "*"
     destination_port_range      = "23"
     source_address_prefix       = "/0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative10" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "23 ,  69"
     source_address_prefix       = "0.0.1.0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}

resource "azurerm_network_security_rule" "negative11" {
     name                        = "example"
     priority                    = 100
     direction                   = "Inbound"
     access                      = "Allow"
     protocol                    = "TCP"
     source_port_range           = "*"
     destination_port_range      = "2,310"
     source_address_prefix       = "0.0.0.0"
     destination_address_prefix  = "*"
     resource_group_name         = azurerm_resource_group.example.name
     network_security_group_name = azurerm_network_security_group.example.name
}