The usage of websites and other internet-backed portals has increased tremendously, more so, during the lockdown period. With more and more content becoming available online, logging in to various websites has become a part and parcel of our daily lives. When you log in to any of the websites, every time a new session is created it remains active until you end it or log out. These sessions can be described as a type of communication between two systems. This high dependency on using the internet comes with a high vulnerability in the form of Session Hijacking.
Every time you log in, you are opening yourself up for an attack by hackers which is why it is vital that you educate yourself about session hijacking. In this post, we will take a look at what exactly Session Hijacking means, what are the different ways in which attackers can hijack a session, the tools used for session hijacking, the preventive measures that you take against Session Hijacking, and more!
Table of Contents
What is Session Hijacking?
Session Hijacking can be defined as the process wherein an attacker takes control of the user’s session by generating a session ID while it is still in use. As mentioned earlier, a session begins when the user logs in to the website. In order to ensure that users enjoy a seamless user experience without having the need to be prompted for authentication every time they log in, a session ID is assigned by the server. Hijackers use various tools and methods to hijack the session, making the user lose control of their session, and putting all their personal data at risk.
Here’s an example to give you an idea about the scope of session hijacking and how it can affect you. Imagine you are browsing through your personal email account or any banking website, and your session gets hijacked – the attacker can easily steal all your data and access all your accounts. The attacker will start communicating with the system posing as you, thus, gaining unauthorized access to all your personal accounts and information. So, how does this work? The attackers use different methods to either steal the user’s session ID or manipulate them to click on malicious links which takes them to a pre-designed session from where they can steal your session ID. Once the ID is stolen, the hacker can easily fool the server into believing that they are authentic users.
Once the attacker gains unlawful authorization, there is no limit to what they can do with your data. From changing passwords that would essentially lock out the user from their own accounts to changing security questions and registered phone numbers, to transferring funds, to stealing identity – there is a lot that attackers can do, causing havoc in your lives.
Also known as cookie hijacking, there are several ways in which attackers can hijack your sessions and it is important to be aware of these methods so that you can better protect your data and yourself.
Different Ways to Hijack a Session
As mentioned earlier, there are different ways to hijack a session, and the attackers can either use these methods individually or as a combination. Below are the top five ways in which hijackers can steal your session.
- Cross-site Scripting – In this type of attack, the attackers try to manipulate the user’s computer, leading them to execute a code that may look trustworthy but is actually malicious in nature. Known to be one of the most common ways of session hijacking, if your web server is not strong enough, the attacker can easily inject scripts (usually JavaScript). When the user clicks on the link with the malicious script, a copy of the user’s session cookie is sent to a site controlled by the hacker. Hence, it is important that your server sets HTTPOnly attributes in the session cookies.
- Malware Injection – Malware is another common way through which hijackers can get access to the session cookies. When the user clicks on a malicious link or visits such websites, it installs the malware which scans the network and sends back the cookie data, thus, allowing the attacker to gain unauthorized access to your data. In some cases, the malware may also get the user’s cookies directly from the local storage of the browser.
- Brute Force – In this type of session hijacking, the hacker tries to guess the session ID to hijack the session. Earlier, this was the preferred method of session hijacking as the session IDs generated by the server used sequential patterns which made these session IDs more vulnerable to such attacks. But today, the majority of the websites generate long and randomly generated session IDs, making it difficult for the hijackers to guess.
- Session Side Jacking – This is another common type of session hijacking that relies majorly on users accessing websites via unsecured public or private Wi-Fi. Another requirement for this type of attack is that the website should be using HTTPS only for the login page and not when the authenticated user is navigating through the website. Once the attacker has this knowledge, they will opt for session sniffing to access the user’s session cookies.
- Session Fixation – As the name suggests, in this type of attack, the hijacker tries to steal the user’s cookies by trying to ‘fix’ the session. For this to work, the attacker needs to already possess a known session ID. The hijacker will then use methods like phishing to convince the user to click on a link that will take them to the ‘fixed’ session. Once the user is authenticated, the hijacker can use the known session ID to hijack the session.
Levels of Session Hijacking
There are two levels of Session Hijacking – The transport layer and the Application layer.
- Transport Layer Hijacking – This level of hijacking occurs majorly in Transmission Control Protocol (TCP) connections. The hijacker interrupts the exchange of data between the user and the server. Then they send out malicious links which appear as legitimate ones to the user as well as the server, thus, accessing and controlling the session. IP spoofing is the most common type of transport layer hijacking wherein the hijacker uses an incorrect IP address to communicate with the other computers on the network.
- Application Layer Hijacking – A Man-in-the-Middle (MiiM) attack is one of the most common types of application layer hijacking wherein the hijacker steals the user’s session ID once they are authenticated. Proxy attacks are also a type of application layer hijacking where the hacker uses a predefined session ID to direct the traffic towards a proxy server.
Types of Session Hijacking
There are three different types of session hijacking:
- Active Session Hijacking – As the name suggests, in this type of session hijacking, the attacker accesses an active connection. By taking over the active connection, they can mute all the devices and take complete control over the communication between the server and the user. Once this is done, they leave the affiliation in between. To interrupt the communication between the server and the user, the attackers usually direct huge amounts of traffic to attack the valid session, leading to a Denial of Service (DoS) attack.
- Passive Session Hijacking – Though this type of session hijacking is similar to the active session hijacking, the difference lies in the fact that the attacker only monitors the communication rather than actually blocking out the user from the session.
- Hybrid Session Hijacking – This type of session hijacking involves a combination of both active and passive session hijacking. In a hybrid hijack, the attackers will monitor the traffic on the network and once they find an issue, they will take over the session and start behaving as legitimate users. The hybrid attack depends on spoofing attacks, such as blind spoofing attacks and non-blind spoofing attacks.
Tools used for Session Hijacking
There are several tools available that can be used by attackers to hijack a session. Some of these tools include:
- Hamster and Ferret – In this tool, the Ferret is responsible for collecting the data and the Hamster behaves like a proxy server and manipulates the collected data which helps them to take control of the session cookies that go through the network.
- T-Sight – T-Sight was originally developed as a network monitoring tool, but it is possible for attackers to perform session hijacking while networking monitoring as well. Hence, the T-Sight software license is now provided only to pre-determined IP addresses.
- Juggernaut – Next in our list of session hijacking tools is Juggernaut which is a network sniffing tool. Attackers can use and configure Juggernaut to monitor all the traffic in a local area network or focus on a particular session ID.
Apart from these tools, some of the other tools used for session hijacking include IP-Watcher, Hjksuite, Hunt, TTY-Watcher, Wireshark, 1164, SSHMITM, etc.
Measures to Prevent Session Hijacking
Now that we have a fair idea of what is Session Hijacking, what are its consequences, the tools used for session hijacking, etc., let’s take a look at how you can prevent session hijacking and what are the preventive measures that you need to have in place.
- Public Wi-Fi – Avoid using public Wi-Fi as much as possible, especially when you are carrying out personal activities, such as shopping online, any type of financial transaction, accessing your social media platform, checking emails, etc. Any hacker around your vicinity can easily use packet sniffing to access your session cookies and other data.
- Session Key – it is recommended that session keys are regenerated after the initial authentication. This will make the session IDs hijacked by the hackers useless, thus, helping you prevent any theft of your session IDs and information.
- Scams – Be aware of any scams, such as requests for clicking on links that have not been sent from legitimate sources. It is possible for session hijackers to send you emails with links that when clicked may install the malware in your systems or redirect you to a page wherein you will log in using a session ID created by the hacker.
- VPN – If there is a need for you to use public Wi-Fi, it is recommended that you get a Virtual Private Network (VPN). This will hide your IP address and keep all your activities safe, secure, and private.
- Security Software – A robust security software is one of the best ways to prevent session hijacking. Installing a strong and popular security software will help you to detect any viruses and also prevent hijackers from injecting malware into your systems.
- HTTPS – Ensure that you are implementing HTTPS on all your web pages so that the hijackers cannot access any of your session IDs.
Conclusion
So, there you have it – a complete guide on session hijacking and the best ways to prevent your sessions from getting hijacked! Keeping your data safe and secure is absolutely important because if it gets into the hands of the hijackers, they can not only steal your data but also cause identity theft. Hence, we highly recommend users be proactive in ensuring that they have all the safety measures in place. Also, since hackers are always looking out for new tools and technologies to carry out these attacks, users should also ensure that they conduct regular checks of their safety measures.
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