Testing for Weak or unenforced username policy (OTG-IDENT-005)

This article is part of the new OWASP Testing Guide v4.

Back to the OWASP Testing Guide v4 ToC:
   https://www.owasp.org/index.php/OWASP_Testing_Guide_v4_Table_of_Contents
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   https://www.owasp.org/index.php/OWASP_Testing_Project

Summary

User account names are often highly structured (e.g. Joe Bloggs account name is jbloggs and Fred Nurks account name is fnurks) and valid account names can easily be guessed.

Test objectives

Determine whether a consistent account name structure renders the application vulnerable to account enumeration. Determine whether the application's error messages permit account enumeration.

How to test

• Determine the structure of account names.

• Evaluate the application's response to valid and invalid account names.

• Use different responses to valid and invalid account names to enumerate valid account names.

• Use account name dictionaries to enumerate valid account names.

Remediation

Ensure the application returns consistent generic error messages in response to invalid account name, password or other user credentials entered during the log in process.