Secure Code Review (SCR) : A2 Broken Authentication and Session Management

Secure Code Review: A2 Broken Authentication and Session Management

In the realm of software security, one of the most critical vulnerabilities that can be exploited by attackers is broken authentication and session management. This vulnerability can allow an attacker to impersonate another user and gain unauthorized access to sensitive data and functionalities. In this blog post, we will delve into the details of broken authentication and session management vulnerabilities, how to identify them during a secure code review, and what measures can be taken to prevent them.

Understanding Broken Authentication and Session Management

Broken authentication and session management vulnerabilities occur when an application fails to properly protect and validate the credentials and session identifiers that are used to identify a user. This can allow an attacker to impersonate another user and gain unauthorized access to their data and functionalities.

These vulnerabilities can occur due to a variety of reasons, such as:

• Inadequate protection of credentials during transmission and storage.
• Insufficient session expiration, allowing an attacker to use a session ID even after the user has logged out.
• Session fixation, where an attacker can force a user to use a session ID known to the attacker.
• Inadequate session invalidation after a successful password change.
• Exposing session IDs in the URL (URL rewriting).

Identifying Broken Authentication and Session Management in Code Review

During a secure code review, the primary goal is to identify places in the code where the application handles user authentication and session management. Here are some things to look for:

1. Insecure transmission of credentials: If the application transmits credentials over an insecure channel (non-HTTPS), it’s a potential vulnerability.
2. Insecure storage of credentials: If the application stores credentials in plaintext or uses weak hashing algorithms, it’s a potential vulnerability.
3. Insufficient session expiration: If the application does not properly expire sessions, it’s a potential vulnerability.
4. Session fixation: If the application does not properly handle session IDs, it’s a potential vulnerability.
5. Inadequate session invalidation: If the application does not invalidate the session after a successful password change or logout, it’s a potential vulnerability.

Checklist for Secure Code Review against Broken Authentication and Session Management

Here is a checklist to follow when performing a secure code review to identify broken authentication and session management vulnerabilities:

1. Identify all points in the code where the application handles user authentication and session management.
2. Check if the application transmits and stores credentials securely.
3. Check if the application properly expires sessions.
4. Check if the application properly handles session IDs to prevent session fixation.
5. Check if the application invalidates the session after a successful password change or logout.

Preventing Broken Authentication and Session Management

Preventing broken authentication and session management vulnerabilities involves proper design and coding practices. Here are some measures that can be taken:

1. Secure transmission of credentials: Always transmit credentials over a secure channel (HTTPS).
2. Secure storage of credentials: Always store credentials securely. Use strong, salted hashing algorithms for password storage.
3. Proper session expiration: Always expire sessions after a period of inactivity or after the user logs out.
4. Prevent session fixation: Always assign a new session ID to a user when they authenticate.
5. Proper session invalidation: Always invalidate the session after a successful password change or logout.

In conclusion, broken authentication and session management is a serious threat to application security, but they can be effectively mitigated with proper coding and design practices. A thorough secure code review is a crucial step in identifying and fixing these vulnerabilities before the application goes into production.

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References:

1. https://owasp.org/www-project-code-review-guide/assets/OWASP_Code_Review_Guide_v2.pdf