IDS and IPS definition

The rise of different types of attacks on the internet has pushed firewall solutions to increase their defense mechanisms. A layer 4-only approach became inefficient against more sophisticated attacks, such as techniques that are used to exploit a known vulnerability, requiring a new approach to detect and block the latest threats. Let's look at a practical example.

Suppose that a layer 4-only firewall allows LAN to internet-only connections to well-known internet protocols such as DNS and HTTP, and connections that are used for email communication, such as POP3, SMTP (submission), and IMAP. So, to bypass the firewall, the attacker could install malware that uses the same ports as the HTTP protocol, such as 80 and 443, so that the malware can transmit data using an allowed port without any problem. Now, suppose that this kind of technique became a trend, and all attackers started bypassing firewalls in this way! Cybersecurity professionals would get...