Introduction to CEH Module 11: Session Hijacking

As cyber threats evolve, understanding and mitigating session hijacking becomes crucial for safeguarding digital assets. In module 11 of CEH, you will dive into session hijacking attacks—a sneaky cyber attack where attackers exploit web sessions to gain unauthorized access to information. Designed for aspiring Ethical Hackers and cybersecurity enthusiasts, this module will equip you with the knowledge and skills to detect, prevent, and defend against these sophisticated attacks. Get ready to empower yourself with cutting-edge cybersecurity techniques and stay ahead in the ever-changing cybersecurity landscape.

What is Session Hijacking?

Have you ever wondered how safe your online sessions are? Have you considered what happens when you log into a website and browse around? Imagine you’re having a secure, private conversation online. You think it’s just between you and the other person, but what if someone else is listening in and even joining the conversation without you knowing? This sneaky eavesdropper is similar to a hacker in session hijacking.

When you log into a website, the server sends a special key, called a session token, to your computer. This key is like a VIP pass that lets you move around the website without needing to log in again whenever you click a new page.

How Does Session Hijacking Work?

• The Set-Up: You log into a website and send a session token to your computer. Think of it as a secret handshake that helps the website identify you.
• The Steal: While browsing, a hacker intercepts the communication and steals your session token. This can happen if the hacker is on the same network or the website doesn’t protect the token well.
• The Takeover: With your session token, the hacker can pretend to be you. They can access your account, see your private information, and even act like you.

Why is Session Hijacking Successful?

Session hijacking is a sneaky cyber attack where hackers take control of your online sessions. But why is it so successful? Let’s understand this:

• Absence of Account Lockout for Invalid Session IDs: Many websites don’t lock out accounts after multiple failed attempts to guess session IDs, allowing hackers to keep trying until they succeed.
• Indefinite Session Timeout: Some websites never log you out automatically, keeping your session active indefinitely. This gives hackers more time to hijack your session.
• Weak Session-ID Generation Algorithm: If a website uses a weak method to create session IDs, hackers can easily guess or predict these IDs. Weak or small session IDs are easier targets.
• Insecure Handling of Session IDs: Some websites don’t properly protect session IDs during transmission. Hackers can intercept and steal these IDs if they are not securely handled.
• Most Computers Using TCP/IP are Vulnerable: The widespread use of the TCP/IP protocol means that many systems are potentially vulnerable to session hijacking if they are not properly secured.
• Most Countermeasures Do Not Work Without Encryption: Many security measures are ineffective if data isn’t encrypted. Encryption is crucial for protecting session IDs and preventing hijacking.

Types of Session Hijacking

There are two main types of session hijacking: passive and active. Let’s break them down in an easy-to-understand way.

Passive Session Hijacking

Imagine you’re having a conversation with a friend. Now, picture someone secretly listening to everything you say without interrupting. That is passive session hijacking.

How it works:

• Listening In: The attacker uses special tools called “sniffers” to eavesdrop on the network traffic between you and the service.
• Gathering Information: They collect important information like your username and password.
• Future Use: The attacker doesn’t use the information immediately but saves it to log in as you later, enjoying the same access and privileges you have.

Why it happens: This type of attack is simple because the attacker just needs to observe and record the traffic. They don’t interfere with the session in real time.

How to protect against it:

• Identification Schemes: Using methods like one-time passwords that change frequently.
• Ticketing Identification: Systems like Kerberos which issue tickets for user authentication.

Active Session Hijacking

Active Session Hijacking is like taking over a conversation. The attacker actively manipulates the session to gain control.

How it works:

• Taking Over: The attacker actively interferes with your ongoing session.
• Manipulating Data: They might alter the data being sent or inject new data to gain control.
• Direct Access: This allows the attacker to do things as if they were you, like sending messages or accessing restricted information.

Why it happens: The attacker is more involved, directly manipulating the session to take control.

How to protect against it:

• Encryption: Ensuring that data transmitted is encrypted makes it much harder for attackers to interfere.
• Digital Signatures: Adding digital signatures ensures the integrity and authenticity of the data.

Spoofing vs. Hijacking

There are two common methods of cyber-attacks: spoofing and hijacking.

Aspects	Spoofing	Hijacking
Definition	An attacker pretends to be another user or machine (victim) to gain access.	The process of seizing control of an existing active session.
Method	The attacker uses stolen credentials to initiate a new session	The attacker relies on the legitimate user to create a connection and then takes over the session.
Process	1. Attacker steals user credentials. 2. Attacker logs in as the user to start a new session.	1. Attacker monitors an active session. 2. Attacker intercepts or predicts session details to take over.
Nature of Attack	Less aggressive, does not interfere with existing sessions.	More aggressive, involves taking control of an ongoing session.
Protection Measures	1. Use strong passwords. 2. Enable two-factor authentication (2FA). 3. Monitor for unusual activity.	1. Encrypt sessions. 2. Use session timeouts. 3. Monitor for unusual activity.
Outcome	Attacker gains access by pretending to be the legitimate user in a new session.	Attacker gains control of an active session, potentially accessing or manipulating data.

How to Protect Against Session Hijacking?

Here are several strategies to help protect your sessions from being hijacked:

1. Use Secure Shell (SSH): Create a secure communication channel using SSH to encrypt your data.
2. Implement Log-Out Functionality: Ensure users can easily log out to end their sessions securely.
3. Generate Unique Session IDs: Create a unique session ID after each successful login and only accept session IDs generated by the server.
4. Encrypt Data in Transit: Use encryption to protect data being transmitted and implement a defense-in-depth mechanism.
5. Use Strong Session Keys: Utilize long and random numbers as session keys for added security.
6. Different Usernames and Passwords: Encourage users to use different usernames and passwords for various accounts to minimize risk.
7. Implement Session Timeouts: Automatically destroy sessions after a period of inactivity to prevent unauthorized access.
8. Avoid Including Session IDs in URLs: Do not include session IDs in the URL or query strings to avoid exposing them.
9. Keep Protection Software Updated: Ensure both client-side and server-side protection software are active and up-to-date.
10. Use Strong Authentication: Implement strong authentication methods like Kerberos or use peer-to-peer VPNs for secure connections.
11. Configure Spoof Protection Rules: Set up internal and external spoof protection rules on network gateways.
12. Monitor ARP Cache Poisoning: Use IDS products or tools like ARPwatch to monitor and detect ARP cache poisoning.
13. HTTP Public Key Pinning (HPKP): Utilize HPKP to allow users to authenticate web servers and ensure secure connections.
14. Verify Website Authenticity: Enable browsers to verify the authenticity of websites using network notary servers.

Master CEH with InfosecTrain

Ethical hacking is a complex and multi-phase process that requires deep knowledge and security certifications. Professionals can improve their security assessment and network architecture skills through ethical hacking courses, such as the Certified Ethical Hacker training provided by InfosecTrain. This training provides individuals with the essential skills and methods needed to perform sanctioned hacking into organizations.

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