According to established incident response frameworks, the phase immediately following the detection and analysis of an incident is containment. The primary objective of the containment phase is to stop the incident from spreading and to limit its impact on business operations and data. By focusing on limiting the damage, the incident response team takes immediate, necessary actions—such as isolating the affected network subnet—to prevent the virus from propagating further. This step is critical and must be performed before any attempts at eradication or recovery to ensure the problem does not escalate.

A. Verifying that the compromised systems are fully functional is a step within the recovery phase, which occurs after the threat has been contained and eradicated.

C. While documentation is a continuous process, the immediate tactical priority after identifying an outbreak is containment, not comprehensive documentation.

D. Removing the virus (eradication) and restoring systems (recovery) are subsequent phases that should only be initiated after the incident has been successfully contained.

1. Cichonski

P.

Millar

T.

Grance

T.

& Scarfone

K. (2012). Computer Security Incident Handling Guide (NIST Special Publication 800-61

Rev. 2). National Institute of Standards and Technology. Section 3.3

"Containment

Eradication

and Recovery

" states

"Containment is the first step in this phase... Containment is important before an incident overwhelms resources or increases damage." (p. 26). https://doi.org/10.6028/NIST.SP.800-61r2

2. ISACA. (2019). CISA Review Manual

27th Edition. Domain 4: Information Systems Operations and Business Resilience. The manual outlines the incident management process

emphasizing that after detection and analysis

the immediate response is to contain the incident to limit the extent of the damage.

3. Carnegie Mellon University Software Engineering Institute. (2017). CSIRT Services. "Containment: Limiting the scope and magnitude of the event." This is listed as a primary service and a critical step in the incident handling process

following initial analysis. Retrieved from https://resources.sei.cmu.edu/assetfiles/WhitePaper/2017019001503734.pdf (p. 5).