[Mimedefang] New spam technique
David F. Skoll
dfs at roaringpenguin.com
Mon Jul 5 10:50:52 EDT 2004
On Fri, 2 Jul 2004, Penelope Fudd wrote:
> Recently spammers verified their mailing list using this SMTP dialogue.
This is an old technique called a "dictionary attack" or "directory
harvesting".
Sendmail 8.13 has countermeasures, like closing a connection after N bad
SMTP commands.
I run a script from cron that parses the mail log and firewalls off directory
harvesters.
--
David.
More information about the MIMEDefang
mailing list