The detection of covert channels in communication networks is a current security challenge. By clandestinely transferring information, covert channels are able to circumvent security barriers, compromise systems, and facilitate data leakage. A set of statistical methods called DAT (Descriptive Analytics of Traffic) has been previously proposed as a general approach for detecting covert channels. In this paper, we implement and evaluate DAT detectors for the specific case of covert timing channels. Additionally, we propose machine learning models to induce classification rules and enable the fine parameterization of DAT detectors. A testbed has been created to reproduce main timing techniques published in the literature; consequently, the testbed allows the evaluation of covert channel detection techniques. We specifically applied Decision Trees to infer DAT-rules, achieving high accuracy and detection rates. This paper is a step forward for the actual implementation of effective covert channel detection plugins in modern network security devices.