“…The following subsections provide more details on the ML models in Section 3.1, on the DL models in Section 3.2, on other methods in Section 3.3, and on the datasets used in the reviewed studies in Section 3.4. [37] RNN Alexa/DGArchive (63 DGAs), Bambenek (11 DGAs) Koh and Rhodes [38] LSTM OpenDNS/Bader, Abakumov Tran et al [39] LSTM.MI Alexa/Bambenek (37 DGAs) Vinayakumar et al [40] LSTM, GRU, IRNN, RNN, CNN, hybrid (CNN-LSTM) Alexa, OpenDNS/Bambenek, Bader (17 DGAs) Xu et al [41] CNN-based Alexa/DGArchive (16 DGAs) Yu et al [42] LSTM, BiLSTM, stacked CNN, parallel CNN, hybrid (CNN-LSTM) Alexa/Bambenek Akarsh et al [43] LSTM OpenDNS, Alexa/20 public DGAs Qiao et al [44] LSTM Alexa/Bambenek Liu et al [45] Hybrid (BiLSTM-CNN) Alexa/Netlab (50 DGAs), Bambenek (30 DGAs) Ren et al [46] CNN, LSTM, CNN-BiLSTM, ATT-CNN-BiLSTM, SVM Alexa/Bambenek, Netlab (19 DGAs) Sivaguru et al [31] hybrid (RF-LSTM.MI) Alexa, private/DGArchive Vij et al [47] LSTM Alexa/11 DGAs Cucchiarelli et al [34] BiLSTM, LSTM.MI, hybrid (CNN-BiLSTM) Alexa/Netlab (25 DGAs) Highnam et al [48] hybrid (CNN-LSTM-ANN) Alexa/DGArchive (3 DGAs) Namgung et al [49] CNN, LSTM, BiLSTM, hybrid (CNN-BiLSTM) Alexa/Bambenek Yilmaz et al [50] LSTM Majestic/DGArchive (68 DGAs) [53] 2020 Alexa/various Yan et al [54] 2020 Passive DNS data/public blacklists Yin et al [55] 2020 Alexa/Bader (19 DGAs)…”