If your web site needs to have user authentication then most likely it will require user name and password to authenticate user accesses. However as computer system have increased in complexity, so has authenticating users has also increased. As a result the code reviewer needs to be aware of the benefits and drawbacks of user authentication referred to as “Direct Authentication” pattern in this section. This section is going to emphasis design patterns for when users forget user id and or password and what the code reviewer needs to consider when reviewing how user id and passwords can be retrieved when forgotten by the user and how to do this in a secure manner.
Notified user by (phone sms, email) an email where the user has to click a link in the email that takes them to your site and ask the user to enter a new password.
Ask user to enter login credentials they already have (Facebook, Twitter, Google, Microsoft Live, OpenID etc) to validate user before allowing user to change password.
Send notification to user to confirm register and or forgot password.
Send notifications that account information has been changed for registered email. Set appropriate time out value. I.e. If user does not respond to email within 48 hours then user will be frozen out of system until user re-affirms password change.
- The identity and shared secret/password must be transferred using encryption to provide data confidentiality. HTTPS should also be used but in itself should not be the only mechanism used for data confidentiality.
- A shared secret can never be stored in clear text format, even if only for a short time in a message queue.
- A shared secret must always be stored in hashed or encrypted format in a database.
- The organization storing the encrypted shared secret does not need the ability to view or decrypt users passwords. User password must never be sent back to a user.
- If the client must cache the username and password for presentation for subsequent calls to a Web service then a secure cache mechanism needs to be in place to protect user name and password.
- When reporting an invalid entry back to a user, the username and or password should no be identified as being invalid. User feed back/error message must consider both user name and password as one item “user credential”. I.e. “The username or password you entered is incorrect.”
AntiPatterns: Forget password.
- Validate all fields have been completed correctly
- Avoid password fields being wiped out.
- Retain user’s email address between log-in and “Forgotten password” page.
- CAPTCHA should be used aa last resort or not all. CAPTCHA can be hacked.
- OpenID does have security implications (e.i. if a hacker gains access to your OpenID, the hacker now potentially have access to all the sites you use with that OpenID.
- Make sure security questions don’t ask for information that can easily be found on social sites like Facebook. E.I. “Mother’s maiden name”.
- Do not mask user input of password. Show character until next character is typed in. Masking every character only provides security if someone is standing directly over you.
- Do not send a onetime password to allow user to reset his/her password. This password would be stored even if for a short time in clear text and email storage is not the place to store passwords.
- Do not have an error message saying account does not exists for this email address. This could be used to find out if user has an account for a porn or another site if hacker knows users email address.
- Important: Do not allow listing of users. The password reset tokens should be uniquely generated, and be cryptographically secure random. Otherwise a listing of users can be generated from forget password feature.