The correct answer is B. Adversary emulation.
Adversary emulation is a technique that involves mimicking the tactics, techniques, and procedures (TTPs) of a specific threat actor or group to test the effectiveness of the security controls and incident response capabilities of an organization1. Adversary emulation can help identify and address the gaps and weaknesses in the security posture of an organization, as well as improve the readiness and skills of the security team. Adversary emulation can also help measure the dwell time, which is the duration that a threat actor remains undetected inside the network2.
The other options are not the best techniques to meet the CISO's goals. Vulnerability scanning (A) is a technique that involves scanning the network and systems for known vulnerabilities, but it does not simulate a real attack or test the incident response capabilities. Passive discovery is a technique that involves collecting information about the network and systems without sending any packets or probes, but it does not identify or exploit any vulnerabilities or test the security controls. Bug bounty (D) is a program that involves rewarding external researchers or hackers for finding and reporting vulnerabilities in an organization's systems or applications, but it does not focus on a specific threat actor or group.

Proper handling and reporting of existing evidence are important for the investigation and reporting phases of an incident response because they ensure the integrity, authenticity, and admissibility of the evidence in case it needs to be presented in court. Evidence that is mishandled, tampered with, or poorly documented may not be accepted by the court or may be challenged by the opposing party. Therefore, incident responders should follow the best practices and standards for evidence collection, preservation, analysis, and reporting.

Adding the SHA-256 hash of a legitimate Microsoft-signed binary like svchost.exe to detection signatures would result in the indicator firing on the majority of Windows devices. Svchost.exe is a common and legitimate system process used by Windows, and using its hash as an indicator of compromise (IOC) would generate numerous false positives, as it would match the legitimate instances of svchost.exe running on all Windows systems.

An SLA, or Service Level Agreement, is a contract between a service provider and its customers that documents what services the provider will furnish and defines the service standards the provider is obligated to meet. In the scenario described, the missed incident response deadline is a clear indicator of an SLA violation. An SLA usually outlines the metrics by which service is measured as well as remedies or penalties should agreed-upon service levels not be achieved. Unlike a KPI (Key Performance Indicator) which is a quantifiable measure used to evaluate the success of an organization, employee, etc., in meeting objectives for performance, or an MOU (Memorandum of Understanding) which is a formal agreement between two or more parties, an SLA is focused on the performance and quality metrics applicable to the service provided. SLO (Service Level Objective) is related and often part of an SLA, representing the specific measurable characteristics of the SLA such as availability, throughput, frequency, response time, or quality.

The correct answer is B. Allowlisting.
Allowlisting is a technique that allows only pre-approved web-based software to run on a system or network, while blocking all other software. Allowlisting can help prevent unauthorized or malicious software from compromising the security of an organization. Allowlisting can be implemented using various methods, such as application control, browser extensions, firewall rules, or proxy servers12.
The other options are not the best techniques to ensure that users only leverage web-based software that has been pre-approved by the organization. Blocklisting (A) is a technique that blocks specific web-based software from running on a system or network, while allowing all other software. Blocklisting can be ineffective or inefficient, as it requires constant updates and may not catch all malicious software. Graylisting
is a technique that temporarily rejects or delays incoming messages from unknown or suspicious sources, until they are verified as legitimate. Graylisting is mainly used for email filtering, not for web-based software control. Webhooks (D) are a technique that allows web-based software to send or receive data from other web- based software in real time, based on certain events or triggers. Webhooks are not related to web-based software control, but rather to web-based software integration.