Check for Unrestricted MySQL Database Access

Risk level: High (not acceptable risk)

Rule ID: Network-006

Ensure that Microsoft Azure network security groups (NSGs) do not allow unrestricted access (i.e. 0.0.0.0/0) on TCP port 3306 in order to protect against malicious actors and significantly reduce the attack surface. TCP port 3306 is used by the MySQL Database Server, a popular open-source Relational Database Management System (RDBMS) server.

This rule resolution is part of the Cloud Conformity Security & Compliance tool for Azure

Security

To determine if your Azure network security groups allow unrestricted MySQL Database access, perform the following actions:

Audit

To determine if your Azure network security groups allow unrestricted MySQL Database access, perform the following actions:

Using Azure Console

01 Sign in to Azure Management Console.

02 Navigate to All resources blade at https://portal.azure.com/#blade/HubsExtension/BrowseAll to access all your Microsoft Azure resources.

03 From the Subscription filter box, select the Azure account subscription that you want to examine.

04 From the Type filter box, select Network security group to list only the security groups available in the selected Azure subscription.

05 Click on the name of the network security group that you want to examine.

06 In the navigation panel, under Settings, select Inbound security rules to access the list with the inbound rules defined for the selected security group.

07 On the Inbound security rules page, verify the value available in the SOURCE column for any inbound rule with the PORT set to 3306 and the PROTOCOL set to TCP. If one or more rules have the SOURCE set to Any (i.e. 0.0.0.0/0), the selected network security group allows unrestricted traffic on TCP port 3306, therefore the MySQL Database inbound access to the associated Microsoft Azure resource(s) is not secured.

08 Repeat steps no. 5 – 7 for each network security group available in the selected subscription.

09 Repeat steps no. 3 – 8 for each subscription created in your Microsoft Azure cloud account.

Using Azure CLI

01 Run network nsg list command (Windows/macOS/Linux) using custom query filters to list the names of all network security groups (and the name of their associated resource groups) available in the current Azure subscription:

az network nsg list
    --output table
    --query '[*].{name:name, resourceGroup:resourceGroup}'

02 The command output should return a table with requested information:

Name                         ResourceGroup
--------------------------   ------------------------------
cc-app-database-server-nsg   cloud-shell-storage-westeurope
cc-development-server-nsg    cloud-shell-storage-westeurope

03 Run az network nsg rule list command (Windows/macOS/Linux) using the name of the Azure network security group (NSG) that you want to examine and its associated resource group as identifier parameters to describe the MySQL Database inbound rule defined for the selected network security group, using custom query filtering:

az network nsg rule list
    --nsg-name cc-app-database-server-nsg
    --resource-group cloud-shell-storage-westeurope
    --query "[?direction=='Inbound' && access=='Allow' && protocol=='TCP' && destinationPortRange=='3306']"

04 The command output should return the requested security group rule metadata or an empty array, i.e. [], if there are no MySQL Database ingress rules created for TCP port 3306:

[
  {
    "access": "Allow",
    "description": null,
    "destinationAddressPrefix": "*",
    "destinationAddressPrefixes": [],
    "destinationApplicationSecurityGroups": null,
    "destinationPortRange": "3306",
    "destinationPortRanges": [],
    "direction": "Inbound",
    "etag": "W/\"abcdabcd-abcd-abcd-abcd-abcdabcdabcd\"",
    "id": "/subscriptions/abcd1234-abcd-1234-abcd-1234abcd1234/resourceGroups/cloud-shell-storage-westeurope/providers/Microsoft.Network/networkSecurityGroups/cc-app-database-server-nsg/securityRules/MYSQL",
    "name": "MYSQL",
    "priority": 300,
    "protocol": "TCP",
    "provisioningState": "Succeeded",
    "resourceGroup": "cloud-shell-storage-westeurope",
    "sourceAddressPrefix": "*",
    "sourceAddressPrefixes": [],
    "sourceApplicationSecurityGroups": null,
    "sourcePortRange": "*",
    "sourcePortRanges": [],
    "type": "Microsoft.Network/networkSecurityGroups/securityRules"
  }
]

If the "sourceAddressPrefix" attribute value is set to "*", "internet" or "any", the selected network security group (NSG) allows unrestricted traffic on TCP port 3306, therefore the MySQL Database inbound access to the associated Microsoft Azure resource(s) is not secured.

05 Repeat step no. 3 and 4 for each Azure network security group created within the selected subscription.

06 Repeat steps no. 1 – 5 for each subscription available in your Microsoft Azure cloud account.

Remediation / Resolution

To update your Azure NSG rule(s) configuration in order to restrict MySQL Database access to trusted entities only, such as admin IP addresses or IP ranges, perform the following actions:

Using Azure Console

01 Sign in to Azure Management Console.

02 Navigate to All resources blade at https://portal.azure.com/#blade/HubsExtension/BrowseAll to access all your Microsoft Azure resources.

03 From the Subscription filter box, select the Azure account subscription that you want to access.

04 From the Type filter box, select Network security group to list only the security groups available in the selected Azure subscription.

05 Click on the name of the network security group that you want to reconfigure.

06 In the navigation panel, under Settings, select Inbound security rules to access the list with the inbound rules defined for the selected security group.

07 On the Inbound security rules page, click on the non-compliant security group inbound rule that you want to reconfigure (see Audit section part I to identify the right rule).

08 On the selected security group rule configuration panel, perform the following:

Select IP Addresses from the Source dropdown list to allow inbound traffic on TCP port 3306 from trusted IP addresses only.
For Source IP addresses/CIDR ranges, provide the source IP address, IP addresses or IP address ranges that will be allowed to access the Azure resources (e.g. virtual machines) associated with the selected network security group (NSG). You can specify a single value or comma-separated list of multiple values. An example of multiple values is 192.168.0.160/32, 10.0.5.30/32.
Leave the rest of the NSG configuration settings unchanged, then click Save to apply the changes.

09 Repeat steps no. 5 – 8 for each network security group that allows unrestricted inbound access on TCP port 3306 (MySQL Database), available in the selected Azure subscription.

10 Repeat steps no. 3 – 9 for each subscription created in your Microsoft Azure cloud account.

Using Azure Console

01 Run network nsg rule update command (Windows/macOS/Linux) using the name of the network security group rule that you want to reconfigure as identifier parameter (see Audit section part II to identify the right NSG rule) to restrict MySQL Database access on TCP port 3306 to trusted IP address(es) only by setting the --source-address-prefixes parameter to the IP address, IP addresses or IP address ranges that are allowed to access the Azure resource(s) associated with the selected network security group. You can specify a single value or a space-separated list of multiple values, as shown in the example below:

az network nsg rule update
    --name MYSQL
    --nsg-name cc-app-database-server-nsg
    --resource-group cloud-shell-storage-westeurope
    --source-address-prefixes 192.168.0.160/32 10.0.5.30/32

02 The command output should return the metadata for the reconfigured Azure NSG rule:

{
  "access": "Allow",
  "description": null,
  "destinationAddressPrefix": "*",
  "destinationAddressPrefixes": [],
  "destinationApplicationSecurityGroups": null,
  "destinationPortRange": "3306",
  "destinationPortRanges": [],
  "direction": "Inbound",
 
  ...
 
  "name": "MYSQL",
  "priority": 300,
  "protocol": "TCP",
  "provisioningState": "Succeeded",
  "resourceGroup": "cloud-shell-storage-westeurope",
  "sourceAddressPrefix": "",
  "sourceAddressPrefixes": [
    "192.168.0.160/32",
    "10.0.5.30/32"
  ],
  "sourcePortRange": "*",
  "sourcePortRanges": [],
  "type": "Microsoft.Network/networkSecurityGroups/securityRules"
}

03 Repeat step no. 1 and 2 for each network security group (NSG) that allows unrestricted inbound access on TCP port 3306 (MySQL Database), available in the current subscription.

04 Repeat steps no. 1 – 3 for each subscription created within your Microsoft Azure cloud account.

References

Azure Official Documentation
Azure network security overview
Network security groups
Create, change, or delete a network security group
Azure best practices for network security

Publication date Oct 26, 2019

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You are auditing:

Check for Unrestricted MySQL Database Access

Risk level: High

Audit

Using Azure Console

Using Azure CLI

Remediation / Resolution

Using Azure Console

Using Azure Console

References

Related Network rules