Lab: Username enumeration via account lock
Summary: PortSwigger's lab demonstrates username enumeration against a login that uses account locking, where the locking logic contains a flaw. The exercise has the tester enumerate a valid username, brute-force that user's password, and reach the account page, using a Cluster bomb attack with a payload position on the username parameter and a blank payload position at the end of the request body.
What's compelling: Account lockout is often deployed as a brute-force defense, but this lab shows the lock itself can leak which usernames are valid - turning a control meant to stop guessing into the signal that makes it possible.
Read the original at PortSwigger Research ↗
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