Audit Your VPC: Find Accidentally Public Subnets with Python

Day 5: Find Accidentally Public Subnets The most common VPC misconfiguration is not a bad security group rule -- it is a subnet using the main route table when it should not be. Subnets without an explicit route table association inherit the VPC's main route table . If that table has an Internet Gateway route, those subnets are public whether you intended it or not. Here is a quick AWS CLI audit: # Get main route table for your VPC MAIN_RT = $( aws ec2 describe-route-tables \ --filters Name = vp