What is a major limitation of a Stateless Packet Filter firewall?

A major limitation of a Stateless Packet Filter firewall lies in its inability to track the state of network connections. Unlike stateful firewalls, which understand and remember the state of active connections, stateless firewalls inspect each packet independently, without context of previous packets. This fundamental design makes them susceptible to various evasion techniques, one of which involves attackers manipulating the transmission of packets.

Specifically, attackers can send ACK packets that may not correspond to any legitimate or established connection. Since the stateless firewall evaluates packets based solely on predefined rules and does not track the state of the flow, these ACK packets might be deemed legitimate and allowed through without proper examination of the surrounding traffic. This presents a significant security risk, as it allows unauthorized access or can facilitate other malicious activities by exploiting the stateless nature of the filtering process.

This limitation highlights the importance of employing advanced firewall solutions, such as stateful firewalls, which maintain awareness of ongoing communications and enhance security by enforcing rules based on the current state of the connection.