According to CEH v13 Module 06: Malware Threats, when analyzing suspicious system behavior or investigating a suspected Trojan infection, a common and effective approach is to:

Monitor system activity and network behavior using tools like netstat, Wireshark, and TCPView.

Trojans often create covert channels or backdoors for remote access, which can be identified through unexpected or unauthorized outgoing connections to remote IP addresses or domains.

Using netstat -an or netstat -ano helps identify open ports and active connections, and checking these against known IPs can indicate whether a Trojan is communicating with a Command and Control (C&C) server.

Analysis of Each Option:

A. Use ExifTool and check for malicious content

Incorrect. ExifTool is primarily used for extracting metadata from files, especially images and documents. It is not effective for analyzing executable malware or system behavior post-execution.

B. You do not check; rather, you immediately restore a previous snapshot of the operating system

Incorrect. While restoring from a snapshot might eventually be required, immediate restoration without diagnosis is not a recommended or forensically sound first step. It also prevents root cause analysis.

C. Upload the file to VirusTotal

Partially correct but not sufficient. While uploading the file to VirusTotal is a good step to confirm if the file is known malware, it does not identify whether the machine is currently infected or actively compromised.

D. Use netstat and check for outgoing connections to strange IP addresses or domains

Correct. This method helps detect if the system is making suspicious external connections that are common in Trojan infections.

Reference from CEH v13 Study Guide and Course Materials:

CEH v13 Official Module 06 – Malware Threats, Section: Types of Malware – Trojans, and System Monitoring Tools

CEH v13 eCourseware Lab Manual: "Detecting Trojan Activity using netstat and TCPView"

CEH Engage Range: Malware Investigation Phase – Trojan Behavior Detection