Input validationis the primary defense againstinjection attacks, such as SQL injection or command injection. It ensures thatuser-supplied data is properly sanitizedbefore processing, preventing attackers from injecting malicious code.
* Authentication (A)helps verify user identity but does not prevent injection attacks.
* Secure cookies (B)improve session security but do not address injection vulnerabilities.
* Static code analysis (C)helps identify vulnerabilities in source code but does not actively prevent attacks in real-time.

An air-gapped network is a network that is physically isolated from other networks, such as the internet, to prevent unauthorized access and data leakage. However, an air-gapped network can still be compromised by removable devices, such as USB drives, CDs, DVDs, or external hard drives, that are used to transfer data between the air-gapped network and other networks. Removable devices can carry malware, spyware, or other malicious code that can infect the air-gapped network or exfiltrate data from it. Therefore, removable devices are the most common data loss path for an air-gapped network. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 9: Network Security, page 449 1

Detailed Explanation:Firewall logs provide details of all network traffic, including connections to and from IoT devices. They are typically the first source of evidence for identifying the time of an exploit. Reference:
CompTIA Security+ SY0-701 Study Guide, Domain 4: Security Operations, Section: "Log Analysis for Incident Response".

The most important security concern when using legacy systems is the lack of vendor support. Without support from the vendor, systems may not receive critical security patches and updates, leaving them vulnerable to exploitation. This lack of support can result in increased risk of security breaches, as vulnerabilities discovered in the software may never be addressed.
References = CompTIA Security+ SY0-701 study materials, particularly in the context of risk management and the challenges posed by legacy systems.