D. Regional Internet registries like ARIN are best queried either via their websites or using tools like Whois. Nmap is a useful port scanning utility, traceroute is used for testing the path packets take to a remote system, and regmon is an outdated Windows Registry tool that has been supplanted by Process Monitor.

A. Honeypots are systems that are designed to look like attractive targets. When they are attacked, they simulate a compromise, providing defenders with a chance to see how attackers operate and what tools they use. DNS sinkholes provide false information to malicious software, redirecting queries about command and control systems to allow remediation. Darknets are segments of unused network space that are monitored to detect traffic – since legitimate traffic should never be aimed at the darknet, this can be used to detect attacks and other unwanted traffic. Crackpots are eccentric people – not a system you’ll run into on a network.

D. Redundant systems, particularly when run in multiple locations and with other protections to ensure uptime, can help provide availability.

B. An authenticated, or credentialed, scan provides the most detailed view of the system. Black-box assessments presume no knowledge of a system and would not have credentials or an agent to work with on the system. Internal views typically provide more detail than external views, but neither provides the same level of detail that credentials can allow.

C. When reading the CVSS 3.0 score, AV is the attack vector. Here, N means network. Confidentiality (C), Integrity (I), and Availability (A) are listed at the end of the listing, and all three are rated as High in this CVSS rating.

A. When Alice encounters a false positive error in her scans, her first action should be to verify it. This may involve running a more in-depth scan like an authenticated scan, but could also involve getting assistance from system administrators, checking documentation, or other validation actions. Once she is done, she should document the exception so that it is properly tracked. Implementing a workaround is not necessary for false positive vulnerabilities, and updating the scanner should be done before every vulnerability scan. Using an authenticated scan might help but does not cover all of the possibilities for validation she may need to use.

C. The Containment, Eradication, and Recovery phase of an incident includes steps to limit damage and document what occurred, including potentially identifying the attacker and tools used for the attack. This means that information useful to legal actions is most likely to be gathered during this phase.

B. Integrity breaches involve data being modified or deleted. Systems being taken offline is an availability issue, protected information being accessed might be classified as a breach of proprietary information, and sensitive personally identifiable information breaches would typically be classified as privacy breaches.

A. Active monitoring sends traffic like pings to remote devices as part of the monitoring process. RMON and netflows are both examples of router-based monitoring, whereas network taps allow passive monitoring.

D. Regular traffic from compromised systems to command and control nodes is known as beaconing. Anomalous pings could describe unexpected pings, but they are not typically part of botnet behavior, zombie chatter is a made-up term, and probing is part of scanning behavior in some cases.

C. The df command is used to show the amount of free and used disk space. Each of the other commands can show information about memory usage in Linux.