Linux VM Without SSH Key

Description

SSH (Secure Shell) provides encrypted communication sessions for Linux VMs in a potentially insecure network. Utilizing SSH keys rather than passwords enhances the security even further. SSH keys are more secure and complex than passwords and are more challenging for attackers to compromise.

This policy checks to ensure that Linux VMs and Linux VM Scale Sets in Azure are configured to use SSH keys for authentication.

Code Example

resource "azurerm_linux_virtual_machine" "example" {
  name                = "example-linux-vm"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
  
  # ... other configurations ...

+ admin_ssh_key {
+   username   = "adminuser"
+   public_key = file("~/.ssh/id_rsa.pub")
  }
}

resource "azurerm_linux_virtual_machine_scale_set" "example" {
  name                = "example-linux-vmss"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
  
  # ... other configurations ...

+ admin_ssh_key {
+   username   = "adminuser"
+   public_key = file("~/.ssh/id_rsa.pub")
  }
}

Remediation

Terraform

Resources:

• azurerm_linux_virtual_machine
• azurerm_linux_virtual_machine_scale_set

Argument:

• admin_ssh_key

Rule Details

Field	Value
ID	IAC-0685
Severity	HIGH
IaC Type	arm
Frameworks	Terraform,
Checkov ID	CKV_AZURE_178

References

• Checkov Rule

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