Session Hijacking

Session hijacking occurs when an attacker steals a valid session ID and uses it to impersonate the legitimate user. This can be achieved through various means:

• Network sniffing - Intercepting unencrypted session cookies on the network
• XSS attacks - Stealing cookies via JavaScript (if HttpOnly is not set)
• Predictable session IDs - Guessing session IDs if they are not sufficiently random
• Session fixation - Forcing a user to use a known session ID

Prevention

• Always use HTTPS with Secure cookies
• Set the HttpOnly flag on session cookies
• Use strong, random session ID generators
• Regenerate session IDs after authentication
• Implement IP binding or user-agent checking as additional verification