In an e-testing system, spoofing may occur if the teacher is unable to see examinees during tests. We examined variations in facial images captured by a webcam during e-testing with the aim of detecting impersonation. In previous work, we proposed an authentication method based on updating an examinee’s facial images, which is limited to VOD-based e-learning. We thus optimized its application to e-testing in this paper. Our findings indicate that the proposed method improves authentication accuracy.