Securing Machine Learning Classifiers with Input Hashing Re-weight Strategy

Adversarial machine learning resides at the intersection of machine learning and computer security. Originally, machine learning techniques were designed for environments that do not assume the presence of an adversary. However, in the presence of intelligent adversaries, this working hypothesis is likely to be violated to at least to some degree, depending on the skillset of an adversary. A skilful adversary can carefully manipulate the input data exploiting specific vulnerabilities of learning algorithms. This results in misclassification of malicious instances, which may compromise the whole system security. For example, by carefully modifying values of features with largest weight without changing the outcome of malicious packet, an adversary may trick an intrusion detection system to allow malicious packet into the network. Solutions presented in research studies by other authors consider the classifier protection using re-weight strategies; typically, this results in compromise between accuracy and robustness. Unlike those, the research presented in this paper deals with a re-weight strategy based on hashing all the numeric features without classification accuracy degradation. System becomes robust as feature weights are even and avalanche effect makes virtually impossible for an attacker to modify the input data and trick the learner into misclassification. Research hypotheses are experimentally validated on custom intrusion detection dataset consisting of numeric features.