Session Hijacking - Deep Dive

What is Session Hijacking?

Session hijacking, also known as session theft, is a type of cyber attack where an attacker takes over a user's session to gain unauthorized access to information or services in a computer system, typically in a web application. The session generally refers to the time interval during which a user interacts with a web server, and during which the server maintains a continuous connection to the user's browser.

Here’s how it generally works:

1. Session Establishment: When a user logs into a website, a session is established between the user’s browser and the server. This session is maintained by a session token or cookie, which is a unique string of characters the server sends to the user's browser. The browser then sends this token back to the server with each subsequent request, verifying the user’s identity without requiring a username and password every time.

2. Attack Execution: In session hijacking, an attacker captures this session token through various means, such as packet sniffing (intercepting data packets as they travel across the network), cross-site scripting (embedding malicious scripts into web pages viewed by other users), or predicting the session token due to weak generation algorithms.

3. Session Takeover: Once the attacker obtains the session token, they can use it to impersonate the victim, accessing sensitive information and performing actions as if they are the legitimate user. This can lead to data theft, financial loss, or unauthorized actions within a secured environment.

Preventive Measures include:

• Using secure connections (HTTPS) to encrypt the data between the client and the server.

• Implementing strong session management policies such as generating complex, unpredictable session IDs, setting appropriate cookie attributes like HttpOnly and Secure, and ensuring session timeout after inactivity.

• Educating users about security best practices, such as avoiding the use of public Wi-Fi for accessing sensitive accounts.

Session hijacking is a significant security threat because it allows attackers to bypass traditional authentication methods, giving them the same privileges as the victim within the application or system.

More resources

Podcast Episodes

What is Session Hijacking? with Tim Tomes