Session Hijacking: What is It, Its Types, and How it Works?

Quick Summary: While the internet is the most useful thing today, it is not free of problems and challenges. There are various cyber security threats that pose real challenges for internet users. Session hijacking is one of those dangers that enable an attacker to obtain control over a user’s web session and exploit it for various malicious purposes. This article sheds light on this threat, helping you understand every aspect in detail, and puts down some ways for session hijacking prevention. Read for your enlightenment.

Imagine a scenario when you log in to a website and all of a sudden, an attacker takes control of your session. It is a kind of malicious activity wherein an attacker snatches the control of a user’s browsing session. The attacker misuses the access to the session token by committing fraud and crimes.

According to a report, there are about 2.7 billion worth of assets of Fortune 1000 employees exposed to the dark web. Mostly the reason for this vast data breach was session cookies. This shows the dangers of a session hijacking attack and the financial implications of this.

These attacks can occur due to many reasons primarily vulnerabilities in software and a lack of solid security mechanisms. Attackers can perform session hijacking with or without installing malware and detecting these threats can be challenging.

It is essential to follow the right steps to prevent this malicious attack and safeguard your data. Plus, you need a robust vulnerability scanning tool to identify potential weaknesses to mitigate this type of security risk. In this blog, we are going to discuss session hijacking in detail and the ways to prevent it. Let’s dive into the blog for more details.

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What is Session Hijacking and Its Implications?

In the simplest way, it is an act of obtaining control of a user’s web session maliciously. A session, or more precisely a web session, denotes the amount of time a user logs in to a website or web app to log out. It is the duration of interaction between two endpoints. Both endpoints use a unique session token that ensures a consistent and secure interaction.

A session hijack attack occurs when an attacker successfully gets unwarranted access to a website or web app masquerading as a genuine user by manipulating or stealing a session token. Attackers use various techniques like brute force, cross-site scripting, session fixation, and more to hijack a session. Session hijacking is alternately known as TCP session hijacking and cookie hijacking.

It poses a serious security threat when an attacker takes control of a legitimate user’s internet session. The user’s sensitive information is at risk because the session hijacking can occur when banking or shopping online. The session hijacker masquerades as a user and steals passwords and personal information by taking control of the browsing session.

Some security threats that occur due to session hijacking:

• Identity Theft: A session hijacker can steal and misuse a user’s personal information. The hijacker can commit crimes, take loans, and cause all other misdeeds masquerading as the victim.
• Frauds: Financial fraud is another serious threat that arises due to session hijacking. Once obtaining access to a website or web app masquerading as a legitimate user, the hijacker can do unauthorized financial transactions, transfer money, or shop online.
• Communication Breach: In this highly digital world, confidential communications like secret business meetings are conducted online. A session hijacker can take control of any user’s session and leak confidential information.
• Denial-of-Service (DoS) Attack: A session hijacker can also launch a DoS attack that causes disruption of service or crash.

How Does Session Hijacking Work?

Now that you have enough information about what session hijacking is and its implications, it’s time to discuss the process of session hijacking. Understanding how session hijacking works can help you make the right decisions for web application security testing. Let’s start by knowing the entire web session mechanism.

• Let’s assume that a user wants to access a resource on a web app.
• First, the user will sign in/login to the web with their credentials.
• As soon as the server verifies the credentials, the user is logged in.
• The server provides a response with a unique session ID.
• After the successful login activity, the session started.
• The session ID enables the application to track the user’s activity.
• The browser sends a session termination request when logging out.
• The session is terminated by the server.

Whenever a user logs in successfully, the target website or web app installs a temporary session cookie to the user’s browser. The cookie tracks the user’s activities and has authentication information to help the user stay logged in through an active session. The cookie remains until the user logs out.

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One of the ways to hijack a session is by stealing the session cookie installed on a user’s browser. After stealing the cookie, the hijacker accesses the session ID in the cookie and then takes over control of the session. The hacker can gain access to a session without detection.

The hijacker will misuse the ongoing session to commit crimes, identify theft, and steal financial information. It can include purchasing items, transferring money from the bank account, and more. Hijackers often commit session attacks on busy networks where there are a large number of active users because it is difficult to detect them.

Attackers can use the following methods for a session hijacking attack:

• Predicting: In many cases, session IDs are not random and can be predicted or calculated.
• Brute Force: It is a method where an attacker tries different session IDs until one matches.

For example, an attacker can try different session IDs like:

https://www.example.com/test/XW304343535189099

https://www.example.com/test/VW304354015208031

https://www.example.com/test/VW304334505225073

• Steal: Attackers use many techniques to steal session IDs such as planting trojans on the target system, snooping, or network eavesdropping.

Preventing such attacks is crucial to safeguard sensitive data and your reputation. The best method to combat threats like session hijacking is conducting dynamic application security testing. It performs simulated attacks on running applications to discover vulnerabilities. It helps to detect security weaknesses most reliably and with minimum false positives. Developers can fix these vulnerabilities before they get exploited by a hacker.

Understanding the Various Types of Session Hijacking

There are different forms of session hijacking and each of them occurs for various reasons. But from a broader perspective, session hijacking can be: active or passive. In active hijacking, the attacker steals or gains access to the session token that enables the attacker to take control of the session. In passive hijacking, the attacker collects information surreptitiously and doesn’t take over the session immediately. Let’s check the types of session hijacking.

Session Fixation

In this case, an attacker fools a user with a fake session ID and steals sensitive information. The attacker creates a fake session ID and sends it to the victim by email as a link to lure them to start a session.

Session Sniffing

It is also known as session side jacking and the attacker exploits a network’s weaknesses to monitor network traffic and access session tokens. This attack happens when users access unsecured Wi-Fi networks.

Cross-site Scripting

An attacker exploits vulnerabilities in websites or web apps and injects malicious scripts into web pages. It enables the attacker to access sensitive information even your browser cookies where the session ID is saved.

Man-in-the-Browser Attack

In this type of hijacking attack, the attacker installs malware or trojan to the target system and waits for them to visit a website. The man-in-the-browser malware will perform transactions secretly and it will seem to be genuine because it works from the victim’s system.

What are the Examples of Session Hijacking Attack?

There are a lot of real-world examples of session hijacking attacks where attackers took over user sessions and misused them. The following are some popular examples of such attacks.

Zoom

During the Covid-19 pandemic video-conferencing applications like Zoom became a big hit. While it facilitated users to meet virtually and utilized it for work, get-togethers, and schoolwork, Zoombombing became a huge concern for all stockholders. Zoombombing was an unwanted intrusion into video conference calls to spread obscene or disturbing materials. Hackers and internet-trolls leveraged session vulnerabilities in Zoom to join private calls without permission causing Zoombombing.

Slack

A security researcher identified a session-related vulnerability in Slack in 2017. Attackers could exploit this vulnerability to compel users for fake session redirects that allowed attackers to access their session cookies. As a result, the attacker could gain access to all kinds of data shared within Slack.

GitLab

A security expert discovered a vulnerability in GitLab in 2017 that led to users’ session tokens appearing in the URL. Plus, further investigation also revealed that GitLab used session tokens that didn’t expire. Consequently, attackers could use such tokens to gain unauthorized access to users’ accounts.

How Can You Prevent Session Hijacking?

There are many ways to prevent session hijacking as given below.

• Always update software: Updating software is a solid method to prevent session hijack attacks. Get the latest security patches.
• Use a VPN: The use of a VPN prevents cyber criminals from intercepting web traffic which can help to prevent session hijacking in case of unsecured networks.
• Use multi-factor authentication: It is also a robust method to protect your session from hacking attacks. Using strong passwords is another important method to secure your session.
• Scan regularly for vulnerabilities: Scanning applications for vulnerabilities at regular intervals helps to identify weak spots to fix them and mitigate security risks. You must choose the best web application security assessment tool for this.

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Final Words

With billions of people using the internet every day for online shopping, social networking, banking transactions, and more, security threats have become a bitter truth. Session hijacking has become one of the biggest threats for online users as it enables attackers to seize their web sessions while masquerading as valid users. It exposes their financial and personal details without detection and prevention.

You need the best security testing tools like ZeroThreat to identify and mitigate such security risks. ZeroThreat is an advanced DAST tool that helps to prevent session hijacking with its cutting-edge scanning features. It can detect vulnerabilities most accurately with zero false positives and offers faster scanning speed.

ZeroThreat offers an AI-driven crawler that can scan web applications meticulously to discover potential security weaknesses. It provides priority-based reports to expedite your AppSec process. Try it for free and enhance the security of your web applications with accurate vulnerability scanning results.