Which technique is used to evade firewalls?

The technique known as packet fragmentation is often employed to evade firewalls by breaking down IP packets into smaller fragments, which may allow certain parts of the data to bypass the firewall rules if it doesn't recognize those fragments accurately. This means that malicious data can be sent in such a way that it can remain undetected by intrusion detection systems or even circumvent security rules put in place by a firewall.

ICMP tunneling exploits the Internet Control Message Protocol (ICMP) to encapsulate other types of IP traffic, allowing data to be transmitted in a format that may not be scrutinized as thoroughly by firewalls. By tunneling data within ICMP packets, attackers can communicate or transfer harmful data without being blocked by conventional firewall settings that target specific protocols or ports.

Banner grabbing, while primarily a technique to gather information about a service running on an open port, can also be associated with evasion techniques. Attackers may utilize this to exploit system services and mislead security measures, although this is more about information gathering than direct evasion.

Given that all these techniques—packet fragmentation, ICMP tunneling, and banner grabbing—can be part of a larger strategy to evade or mislead firewall protections, it's accurate to state that they all contribute to the ability to