CAPEC-50 Detail

An attacker may take advantage of the application feature to help users recover their forgotten passwords in order to gain access into the system with the same privileges as the original user. Generally password recovery schemes tend to be weak and insecure.

Execution Flow

Understand the password recovery mechanism and how it works.

Find a weakness in the password recovery mechanism and exploit it. For instance, a weakness may be that a standard single security question is used with an easy to determine answer.

Prerequisites

The system allows users to recover their passwords and gain access back into the system.
Password recovery mechanism has been designed or implemented insecurely.
Password recovery mechanism relies only on something the user knows and not something the user has.
No third party intervention is required to use the password recovery mechanism.

Skills Required

Brute force attack
Social engineering and more sophisticated technical attacks.

Resources Required

For a brute force attack one would need a machine with sufficient CPU, RAM and HD.

Mitigations

Use multiple security questions (e.g. have three and make the user answer two of them correctly). Let the user select their own security questions or provide them with choices of questions that are not generic.
E-mail the temporary password to the registered e-mail address of the user rather than letting the user reset the password online.
Ensure that your password recovery functionality is not vulnerable to an injection style attack.

Related Weaknesses

References

REF-429

Advisory: Unauthorized password recovery in phpBannerExchange
http://www.redteam-pentesting.de/advisories/rt-sa-2006-005.txt

Submission

Modifications