Huge amount of users are migrated from wired network to wireless network because of the easy way of deployment, less maintenance and less cost for implementing the wireless networks. In wireless networks, packets are transferred in the air and they do not have any specific boundary range. So wireless networks are insecure against various types of attacks. All the web application involves in obtaining the session with user and web server. It is very important to provide the security for the web sessions. One of the most severe attacks in wireless networks is session hijack attack that hijacks the web sessions. In this paper, we have proposed the Strong Session ID appended with Message Authentication Code (MAC) to prevent the session hijack attacks in web sessions. We have generated the MAC appended Session ID of 3 different lengths of 160 characters, 192 characters and 248 characters. We have tested the integrity of above 3 lengths of the session IDs in a web application for 10 sessions, 20 sessions and 30 sessions. Attacks are executed to capture the session IDs. The number of session IDs prevented and the number of session IDs attacked are recorded for the Session ID length of 160 characters, 192 characters and 248 characters. The experimental results proved that 248 characters of MAC appended Strong Session ID completely prevents the session hijack attacks in wireless networks. © 2017, Institute of Advanced Scientific Research, Inc. All rights reserved.