A network traffic analyzer (also known as a packet sniffer) is the best tool to identify credentials

being transmitted in plaintext, such as those used in Telnet sessions. Since Telnet transmits data

without encryption, a network traffic analyzer can capture the traffic between the client and the

network switches, revealing sensitive information, including login credentials, in clear text. This tool

helps identify insecure protocols and enables remediation by switching to encrypted alternatives like

SSH. CASP+ highlights the importance of using secure protocols and tools like traffic analyzers to

identify vulnerabilities in network communications.

Reference:

CASP+ CAS-004 Exam Objectives: Domain 2.0 – Enterprise Security Operations (Network Traffic

Analysis and Insecure Protocols)

CompTIA CASP+ Study Guide: Monitoring Network Traffic for Plaintext Credentials