The rule titled 'Accepted Default Telnet Port Connection' is designed to detect and alert on network traffic that potentially uses Telnet, a protocol often employed by system administrators for command-line access to legacy systems. Despite its administrative utility, Telnet poses significant security risks as it employs plaintext communication, allowing threat actors to intercept usernames and passwords or exploit the connection for unauthorized access. The detection logic targets events related to network connections specifically on TCP port 23, which is the default for Telnet. The ruleset flags connections that do not exhibit typical security behaviors, such as bypassing standard security measures. This is crucial since Telnet should generally not be directly exposed to the Internet due to its vulnerability to exploitation, particularly by adversaries aiming for initial access or lateral movement within networks. The rule is built on a query that filters for network traffic, specifically looking for connections that are not dropped, denied, or terminated. False positives may arise from legitimate IoT device interactions or internal management protocols utilizing Telnet, emphasizing the need for careful investigation and review of the traffic context. As a response measure, security teams are urged to validate any triggered alerts rigorously by examining source and destination IPs, correlating with user accounts, and employing remediation strategies that include isolating affected systems, terminating sessions, and migrating to more secure protocols such as SSH.