🛠️ Logging in

Theory

link default passwords

Authentication issues are important to take into consideration. A login page can be the beginning of serious issues regarding accounts takeover.

or bruteforce

Practice

or authentication bypass

Brute-force

Brute-forcing can have 2 interesting purposes during a pentest engagement:

1. Verifying that the web application implements security measures against brute-forcing.
2. Taking over an account by guessing its credentials.

One has to check whether a defense mechanism is used (account locking, blocking IP, CAPTCHA, etc.)

Account locking can lead to a denial of service and allow user enumeration. Check the OWASP recommendation on how it should be implemented.

User enumeration

User enumeration can be made possible depending on the:

• Status code (is the status code retrieved, always the same?)
• Error messages (does the error messages give a hint on whether the account exists?)
• Response time (is the response time always the same?)

JSON Web Tokens (JWS) / OAuth 2.0

Check the following pages for issues regarding JWS and OAuth 2.0.

SQL injection

The tool sqlmap can unveil SQL injections on log-in forms.

sqlmap -r $REQUEST_FILE -p $LOGIN_PARAM,$PWD_PARAM

Use the --level and --delay options in pentest engagements to avoid issues (aggressive payloads and denial of service)

For manual testing: SQL injection (PayloadsAllTheThings)

🛠️ NoSQL injection

For manual testing: NoSQL injection (PayloadsAllTheThings)

🛠️ LDAP injection

For manual testing: LDAP injection (PayloadsAllTheThings)

Encrypted requests

Some web applications don't use TLS to encrypt login requests, this can lead to account takeover via a Man-in-the-Middle attack.

Resources

https://portswigger.net/web-security/authentication/password-based

https://portswigger.net/web-security/authentication/securing

https://cheatsheetseries.owasp.org/cheatsheets/JSON_Web_Token_for_Java_Cheat_Sheet.html

https://cheatsheetseries.owasp.org/cheatsheets/Authentication_Cheat_Sheet.html

https://auth0.com/blog/what-is-broken-authentication/

https://owasp.org/www-project-top-ten/2017/A2_2017-Broken_Authentication

https://book.hacktricks.xyz/pentesting-web/login-bypass

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