Use of formal methods is considered as a useful and efficient technique for the validation of security properties of the protocols. In this paper, we analyze the protocols of ISO/IEC 9798-2 entity authentication standard using a state-of-the-art tool for automated analysis named AVISPA. Our analysis of the standard using AVISPA's OFMC and CL-AtSe back-ends shows that the two party protocols are secure against the specified security properties while the back-ends are able to find attacks against unilateral and mutual authentication protocols involving a trusted third party.