Preparation --> Detection and Analysis --> Containment, Erradicaion and Recovery --> Post-Incident Activity Detection and Analysis --> Profile networks and systems, Understand normal behaviors, Create a log retention policy, Perform event correlation. Maintain and use a knowledge base of information.Use Internet search engines for research. Run packet sniffers to collect additional data. Filter the data. Seek assistance from others.
Keep all host clocks synchronized. Know the different types of attacks and attack vectors. Develop processes and procedures to recognize the signs of an incident. Understand the sources of precursors and indicators.
Create appropriate incident documentation capabilities and processes. Create processes to effectively prioritize security incidents. Create processes to effectively communicate incident information (internal and external communications).
Ref: Cisco CyberOps Associate CBROPS 200-201 Official Cert Guide

CDFS stands for Compact Disc File System, which is a file system used by Mac OS to store data on CDs.
CDFS is also known as ISO 9660, which is a standard format for data interchange on optical discs. CDFS allows files to be accessed by different operating systems, such as Windows, Linux, and Mac OS. Therefore, an ISO file that is stored in CDFS format is data from a CD copied using Mac-based system. References := Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) v1.0, Module 4: Network Intrusion Analysis, Lesson 4.4: File Type Analysis, Topic 4.4.1: File Systems, page 4-40.

After a breach has been discovered and the immediate threat has been addressed by identifying and removing the threat's access, the next step according to the NIST SP 800-61 Incident Handling Guide is to recover from the threat. This involves restoring systems to normal operation, confirming that the systems are functioning normally, and applying patches or other remediation measures to prevent similar breaches in the future1.
Reference:
Understanding NIST SP 800-61: The Computer Security Incident Handling Guide

The correct display filter for analyzing FTP traffic in a PCAP file is "tcp.port==21". This filter will show all TCP packets where the port number is 21, which is the standard port for FTP control messages.