Linux is the most renowned open source operating system. In recent years, the number of malware targeting Linux OS has been increased and the traditional defence mechanisms seems to be futile. We propose a novel non-parametric statistical approach using machine learning techniques for identifying previously unknown malicious Executable Linkable Files (ELF). The system calls employed as features extracted dynamically within a controlled environment. The proposed approach ranks and determine the prominent features by using non-parametric statistical methods like Kruskal-Wallis ranking test (KW), Deviation From Poisson (DFP). Three learning algorithms (J48, Adaboost and Random Forest) are applied to generate prediction model, from a minimal set of features extracted from the system call traces. Optimal feature vector resulted in over all classification accuracy of 97.30% to identify unknown malicious specimens.