  Network covert channels are hidden communication channels in computer
networks. They influence several factors of the cybersecurity economy. For
instance, by improving the stealthiness of botnet communications, they aid and
preserve the value of darknet botnet sales. Covert channels can also be used to
secretly exfiltrate confidential data out of organizations, potentially
resulting in loss of market/research advantage. Considering the above, efforts
are needed to develop effective countermeasures against such threats. Thus in
this paper, based on the introduced novel warden taxonomy, we present and
evaluate a new concept of a dynamic warden. Its main novelty lies in the
modification of the warden's behavior over time, making it difficult for the
adaptive covert communication parties to infer its strategy and perform a
successful hidden data exchange. Obtained experimental results indicate the
effectiveness of the proposed approach.
