Lab: Username enumeration via subtly different responses
Summary: PortSwigger's lab demonstrates a login form that is subtly vulnerable to username enumeration and password brute-force attacks, using an account with a predictable username and password drawn from provided wordlists. The intended path is to enumerate a valid username through subtly different responses, then brute-force that user's password with Intruder and access the account page.
Bottom line: The vulnerability is a response that differs only subtly between a valid and invalid username, which is enough for an attacker to confirm accounts before brute-forcing a password - and the lab notes a single cluster bomb attack could also work, though enumerating a valid username first is generally much more efficient.
Read the original at PortSwigger Research ↗
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- Vulnerabilities & Patching
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