In Trojan terminology, what is a covert channel?

A covert channel is a communication path that is not designed for information transfer but can be exploited by malicious software, such as Trojans, to secretly transmit data in violation of a system's security policy. This often involves using legitimate system resources in an unconventional manner.

A legitimate communication path is an overt channel, designed for communication, which is the antithesis of a covert channel.

While rootkits might utilize covert channels, 'a kernel operation that hides boot processes and services' describes a rootkit's specific functionality for evasion, not the general definition of a covert channel.

Reverse tunneling using HTTPS is a specific technique for creating a communication link, which *could* be used to establish a covert channel, but it is not the definition of a covert channel itself.