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Re: [cobalt-security] Weird sendmail occurence -- please advise



Hi Glenn,

> I just saw a strange attack on my Cobalts that serve mail.
>
> Jan 31 11:06:14 mail sendmail[11500]: NOQUEUE: blinky.mydomain.com
> [192.168.5.5]: EXPN root [rejected]
>
> Jan 31 11:06:14 mail sendmail[11500]: NOQUEUE: blinky.mydomain.com
> [192.168.5.5]: VRFY root [rejected]
>
> Can anyone explain what happened here? It looks like I'm getting hacked
> from my firewall!? 

See this: http://www.demarc.com/arachnids/IDS31/research.html

Quote from that page: "expn is a valid part of the SMTP protocol, however it 
is not commonly used to gather information about system accounts such as 
root. This behavior is indicative of a probe."

-- 

With best regards,

Michael Stauber