How do you deal with session hijacking and fixation attacks in web applications?

1 Session hijacking

Session hijacking is an attack where an attacker steals or guesses a valid session ID from a legitimate user and uses it to impersonate them on the web application. Session IDs are usually generated by the server and sent to the client as cookies, hidden form fields, or URL parameters. An attacker can obtain a session ID by sniffing network traffic, compromising the client or the server, or exploiting cross-site scripting (XSS) vulnerabilities. Session hijacking can result in unauthorized access, data theft, or account takeover.

2 Session fixation

Session fixation is an attack where an attacker sets or fixes a session ID for a victim and waits for them to use it to log in to the web application. The attacker can then use the same session ID to access the victim's account. Session fixation can happen when the web application does not validate or regenerate session IDs properly, or when the attacker can manipulate the client's browser or network to accept a predefined session ID. Session fixation can also lead to unauthorized access, data theft, or account takeover.

3 Prevention methods

To prevent session hijacking and fixation attacks in web applications, there are several methods to consider. Utilizing secure and encrypted communication protocols, such as HTTPS, can protect against network sniffing and tampering. Additionally, secure and random session ID generation algorithms should be used, while avoiding exposing session IDs in URLs or forms. Furthermore, session timeout and expiration mechanisms should be employed, invalidating session IDs after logout or inactivity. It is also recommended to use session regeneration or rotation techniques, changing the session IDs after login or sensitive actions. Additionally, cookie attributes such as HttpOnly, Secure, and SameSite can be used to protect session cookies from XSS and CSRF attacks. Finally, user verification and reauthentication methods such as captcha, password, or OTP should be implemented to confirm user identity before performing critical operations.

4 Testing tools

Testing the security of your web applications against session hijacking and fixation attacks can be done with a range of tools and techniques. Burp Suite is a popular security testing tool that allows for intercepting, modifying, and replaying HTTP requests and responses, as well as analyzing session cookies and tokens. Zed Attack Proxy (ZAP) is an open source web application security testing tool that offers both automated and manual testing features. The OWASP Session Management Testing Guide provides best practices and methodologies for testing session management in web applications, while OWASP WebGoat is a deliberately insecure web application to help identify and exploit various vulnerabilities, including session hijacking and fixation.