Which of these types of threats can the Firebox prevent with the Default Packet Handling settings?

The Firebox's Default Packet Handling settings are primarily designed to mitigate issues such as flood attacks, which involve overwhelming a network with excessive traffic to disrupt services. Flood attacks can manifest in various forms, such as SYN floods, UDP floods, and ICMP floods, all aimed at depleting the resources of the target system or network. The Default Packet Handling settings help in recognizing and filtering out these types of excessive traffic patterns, maintaining the integrity and availability of the network.

In contrast, the other types of threats listed are handled through different mechanisms and require specific preventive measures. For instance, KRACK attacks exploit vulnerabilities in the WPA2 wireless encryption protocol, requiring different security updates or alternative strategies to secure wireless networks. Man-in-the-middle attacks involve interception of communications, which typically necessitates encryption and proper authentication to prevent unauthorized access. Lastly, SQL injection attacks target application vulnerabilities that allow for malicious SQL code to be executed on a database, requiring secure coding practices and web application firewalls rather than packet handling settings alone.

Thus, the Default Packet Handling settings of the Firebox effectively focus on the prevention of flood attacks, ensuring network stability and service uptime against this specific threat.