Explanation:

Based on the logs, it seems that the host that originated the infection is 192.168.10.22. This host has a suspicious process named svchost.exe running on port 443, which is unusual for a Windows service. It also has a large number of outbound connections to different IP addresses on port 443, indicating that it is part of a botnet.
The firewall log shows that this host has been communicating with 10.10.9.18, which is another infected host on the engineering network. This host also has a suspicious process named svchost.exe running on port 443, and a large number of outbound connections to different IP addresses on port 443.
The other hosts on the R&D network (192.168.10.37 and 192.168.10.41) are clean, as they do not have any suspicious processes or connections.

An application allow list is a security technique that specifies which applications are authorized to run on a system and blocks all other applications. An application allow list can best protect against an employee inadvertently installing malware on a company system because it prevents the execution of any unauthorized or malicious software, such as viruses, worms, trojans, ransomware, or spyware. An application allow list can also reduce the attack surface and improve the performance of the system. Reference: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 11: Secure Application Development, page 551 1

A legacy server is a server that is running outdated or unsupported software or hardware, which may pose security risks and compatibility issues. A critical business application is an application that is essential for the operation and continuity of the business, such as accounting, payroll, or inventory management. A legacy server running a critical business application may be difficult to replace or upgrade, but it should not be left unsecured or exposed to potential threats.
One of the best ways to handle a legacy server running a critical business application is to harden it.
Hardening is the process of applying security measures and configurations to a system to reduce its attack surface and vulnerability. Hardening a legacy server may involve steps such as:
* Applying patches and updates to the operating system and the application, if available
* Removing or disabling unnecessary services, features, or accounts
* Configuring firewall rules and network access control lists to restrict inbound and outbound traffic
* Enabling encryption and authentication for data transmission and storage
* Implementing logging and monitoring tools to detect and respond to anomalous or malicious activity
* Performing regular backups and testing of the system and the application Hardening a legacy server can help protect the critical business application from unauthorized access, modification, or disruption, while maintaining its functionality and availability. However, hardening a legacy server is not a permanent solution, and it may not be sufficient to address all the security issues and challenges posed by the outdated or unsupported system. Therefore, it is advisable to plan for the eventual decommissioning or migration of the legacy server to a more secure and modern platform, as soon as possible.
References: CompTIA Security+ SY0-701 Certification Study Guide, Chapter 3: Architecture and Design, Section 3.2: Secure System Design, Page 133 1; CompTIA Security+ Certification Exam Objectives, Domain
3: Architecture and Design, Objective 3.2: Explain the importance of secure system design, Subobjective:
Legacy systems 2

Given the scenario where an Intrusion Detection System (IDS) has detected a high rate of SQL injection attacks and the perimeter firewall is at capacity, the best action would be to set the appliance to Intrusion Prevention System (IPS) mode and place it in front of the company firewall. This approach has several benefits:
Intrusion Prevention System (IPS): Unlike IDS, which only detects and alerts on malicious activity, IPS can actively block and prevent those activities. Placing an IPS in front of the firewall means it can filter out malicious traffic before it reaches the firewall, reducing the load on the firewall and enhancing overall security.
Reducing Traffic Load: By blocking SQL injection attacks and other malicious traffic before it reaches the firewall, the IPS helps maintain the firewall's performance and prevents it from becoming a bottleneck.
Enhanced Security: The IPS provides an additional layer of defense, identifying and mitigating threats in real-time.
Option B (Convert the firewall to a WAF and use IPSec tunnels) would not address the primary issue of reducing traffic to the firewall effectively. Option C (Set the firewall to fail open) would compromise security. Option D (Deep packet inspection) could be resource-intensive and might not alleviate the firewall capacity issue effectively.