Enumerating usernames with Burp Suite - Port Swigger
Summary: PortSwigger's guide describes using Burp Intruder to insert a list of candidate usernames into a login or registration form and then study the responses for behavior that reveals a valid account, such as anomalous error messages, response times, or status codes. In the walkthrough example, the tell is an error message missing a full stop, which Burp's Comparer tab highlights by comparing responses by words or bytes.
Why it matters: A single missing character in an error message is enough to confirm a valid username, and the guide notes that an enumerated list greatly reduces the time and effort needed for a password-guessing attack.
Read the original at PortSwigger Research ↗
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