What is Session Hijacking?
TCP session hijacking is a security attack on a user session over a protected network. The most common method of session hijacking is called IP spoofing, when an attacker uses source-routed IP packets to insert commands into an active communication between two nodes on a network and disguising itself as one of the authenticated users. This type of attack is possible because authentication typically is only done at the start of a TCP session.
Another type of session hijacking is known as a man-in-the-middle attack, where the attacker, using a sniffer, can observe the communication between devices and collect the data that is transmitted.
Different ways of session hijacking :
There are many ways to do Session Hijacking. Some of them are given below –
Using Packet Sniffers
In the above figure, it can be seen that attack captures the victim’s session ID to gain access to the server by using some packet sniffers.
Cross Site Scripting(XSS Attack)
var adr =
Spoofing is pretending to be someone else. This is a technique used to gain unauthorized access to the computer with an IP address of a trusted host. In implementing this technique, attcker has to obtain the IP address of the client and inject his own packets spoofed with the IP address of client into the TCP session, so as to fool the server that it is communicating with the victim i.e. the original host.
If attacker is not able to sniff packets and guess the correct sequence number expected by server, brute force combinations of sequence number can be tried.
- Advanced Session Hijacking and How to Protect Yourself
- Typosquatting/URL Hijacking
- Session Management in HTTP
- Top 10 Programming Languages to Learn in 2020 - Demand, Jobs, Career Growth
- Best Way to Learn NodeJS - A Complete Roadmap
- How to Become a Cyber Security Consultant?
- How to Become a Software Architect?
- Top Programming Languages for Internet of Things
- How to Keep Your Skills Updated As a Software Developer?
- How to Get Started With Open Source Contribution ?
- Top 10 Open-Source NoSQL Databases in 2020
- Top 7 Reasons to Learn Hadoop
- Top 5 Reasons to Contribute to Open Source Project
- AWS vs Azure - Which One You Should Choose?
To defend a network with session hijacking, a defender has to implement both security measures at Application level and Network level. Network level hijacks can be prevented by Ciphering the packets so that the hijacker cannot decipher the packet headers, to obtain any information which will aid in spoofing. This encryption can be provided by using protocols such as IPSEC, SSL, SSH etc. Internet security protocol (IPSEC) has the ability to encrypt the packet on some shared key between the two parties involved in communication. IPsec runs in two modes: Transport and Tunnel.
In Transport Mode only the data sent in the packet is encrypted while in Tunnel Mode both packet headers and data are encrypted, so it is more restrictive.
Session hijacking is a serious threat to Networks and Web applications on web as most of the systems are vulnerable to it.
This article is contributed by Akash Sharan. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.