The most effective and logical next step in an investigation is to gather more context about the observed anomaly. Analyzing the server's outbound traffic patterns and comparing them against historical baselines allows the analyst to determine if the activity is truly malicious or a benign anomaly (e.g., a new service, a large data transfer for a legitimate purpose). This analysis phase is critical for understanding the scope and nature of the event, which informs subsequent actions like containment or escalation. Acting without this analysis, such as immediately disabling the connection, can alert an attacker, destroy volatile evidence, or unnecessarily disrupt business operations.

A. Replacing the network adapter is a drastic and premature step. There is no evidence to suggest a hardware-level compromise, which is far less common than software-based issues.

B. Reporting to law enforcement is a significant escalation that should only occur after an incident has been confirmed and its impact assessed, as per the organization's incident response plan.

C. This is a containment action, not an investigative one. While potentially necessary later, immediate disconnection prevents further live analysis of the attacker's methods and could be an overreaction if the traffic is legitimate.

1. NIST Special Publication 800-61 Rev. 2, Computer Security Incident Handling Guide. Section 3.2, "Detection and Analysis," emphasizes that after detecting a potential incident, the next step is analysis to validate and understand it. Section 3.2.3, "Analyzing the Incident," states, "The analysis should be performed in a structured way... Normal behavior for a network, a system, or an application is often identified by creating a baseline of its characteristics." This directly supports comparing traffic against a baseline.

2. Carnegie Mellon University, Software Engineering Institute, The CERT Guide to Coordinated Vulnerability Disclosure. While focused on vulnerabilities, the underlying principles of investigation apply. Chapter 4, "Incident Management," outlines a process where analysis and characterization of an event precede containment and eradication actions to ensure a measured and effective response.

3. MIT OpenCourseWare, Course 6.857 Computer and Network Security, Fall 2017, Lecture 19 Notes. The lecture on Network Security discusses intrusion detection systems (IDS) and the importance of analyzing alerts. It highlights the need to distinguish true positives from false positives by analyzing traffic patterns and context, which aligns with the correct answer. The process described is one of observation followed by orientation (analysis) before deciding on an action.