Nowadays, cybercriminals are using a diversity of techniques to keep their communication channels and exchanged messages secret and hidden. Information hiding techniques, such as network covert channels, are examples of techniques used to preserve secrecy and guarantee hidden communication channels that cannot be captured or discovered by security and surveillance state agencies. The inclusion of network covert channels in information security curricula is therefore considered a valuable extension. However, information hiding techniques are not covered sufficiently in most information security curricula. In addition, there are few educational publications that discuss teaching approaches of such techniques. This paper contributes to fill this gap by providing a method for teaching network covert channels using a hands-on lab based educational approach. The proposed hands-on lab activities can be used in didactic environments to build and detect network covert channels. The impact of offering the hands-on lab exercises on the students' performance is discussed. Moreover, anonymous questionnaires were administered to students, who participated in the hands-on lab exercises, to evaluate student's self-assessment of acquired skills and identify their overall satisfaction level about the offered hands-on lab exercises.