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SMTP Enumeration
SMTP Enumeration SMTP (port 25) is the email-sending protocol. Enumeration uses commands like VRFY to check which usernames exist. A list of valid users is gold for phishing and password attacks. Seeing VRFY succeed and thinking “hacked”. It only confirms a username; it gives no access. Fix: disable
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What this card says
What it is
SMTP (port 25) is the email-sending protocol. Enumeration uses commands like VRFY to check which usernames exist.
Why it matters for security
A list of valid users is gold for phishing and password attacks.
Common mistake
Seeing VRFY succeed and thinking “hacked”. It only confirms a username; it gives no access.
Fix: disable VRFY/EXPN. Test only in scope.
Learn more in the lesson: 37.5 SMTP Enumeration