Security Group
A virtual firewall in cloud platforms (AWS, GCP, Azure) that controls traffic to and from your server.
A security group is a cloud-based firewall provided by platforms like AWS, Google Cloud, and Azure. It defines which incoming (inbound) and outgoing (outbound) traffic is allowed to reach your cloud server. By default, security groups block all incoming traffic, so you must explicitly open ports like 80 (HTTP), 443 (HTTPS), and 22 (SSH). Misconfigured security groups are the most common cause of cloud data breaches. Accidentally leaving database ports (3306, 5432, 6379) open to the public internet is a critical vulnerability.