A method for detecting an audio adversarial attack with respect to a voice input processed by an automatic speech recognition system, the method being implemented by a detection device connected to the automatic speech recognition system, wherein the method comprises: obtaining an input audio signal associated with the voice input; obtaining a transcript resulting from the processing, by the automatic speech recognition system, of the input audio signal; converting the transcript into a synthesized audio signal associated with a target text-to-speech voice; extracting (15, 15'), at a sampling time interval, at least one acoustic feature of a same type, respectively from the input audio signal and from the synthesized audio signal, delivering a first sequence of features vectors associated with the input audio signal and a second sequence of features vectors associated with the synthesized audio signal; converting (16, 16') the acoustic features of the first sequence of features vectors and the acoustic features of the second sequence of features vectors to corresponding acoustic features associated with a target reference voice, respectively delivering a first sequence of converted features vectors (sCFV1) associated with the input audio signal and a second sequence of converted features vectors (sCFV2) associated with the synthesized audio signal; computing a dynamic time warping distance between the first sequence of converted features vectors (sCFV1) and the second sequence of converted features vectors (sCFV2); and delivering a piece of data representative of a detection of an audio adversarial attack, as a function of a result of a comparison between the dynamic time warping distance and a predetermined threshold. obtaining an input audio signal associated with the voice input; obtaining a transcript resulting from the processing, by the automatic speech recognition system, of the input audio signal; converting the transcript into a synthesized audio signal associated with a target text-to-speech voice; extracting (15, 15'), at a sampling time interval, at least one acoustic feature of a same type, respectively from the input audio signal and from the synthesized audio signal, delivering a first sequence of features vectors associated with the input audio signal and a second sequence of features vectors associated with the synthesized audio signal; converting (16, 16') the acoustic features of the first sequence of features vectors and the acoustic features of the second sequence of features vectors to corresponding acoustic features associated with a target reference voice, respectively delivering a first sequence of converted features vectors (sCFV1) associated with the input audio signal and a second sequence of converted features vectors (sCFV2) associated with the synthesized audio signal; computing a dynamic time warping distance between the first sequence of converted features vectors (sCFV1) and the second sequence of converted features vectors (sCFV2); and delivering a piece of data representative of a detection of an audio adversarial attack, as a function of a result of a comparison between the dynamic time warping distance and a predetermined threshold.