Re: Sendmail DOS ?

[Ken Lyon <ken () vortexcorp com>]

Seems like maybe Michael set up a host monitor and put in the wrong IP?
WhatsUP doesn't issue a "quit" AFAIK but will do all the rest of that
communication. Maybe polling is set for 70 seconds. There are other host monitors out
there and it may be one of those or home grown.
Try web to port 80 or 8080 of the sending IP and see if you get anything?
or... nmap the sending host and try a http connection to the open ports.

I would think it is a simple typo. It may be hard to track Michael down since it
may be a user account on bt.com

...ken

Wednesday, March 27, 2002, 5:30:37 AM (GMT-5), you wrote:
> Greetings,

> i just wondered if anyone can help me out with a possible incident / DOS.
> for the past 10 hours or so i have been getting sendmail log entries like.
> ....
> Mar 27 06:30:19 hostname sendmail[690]: NOQUEUE:
> host*-*-*-*.in-addr.btopenworld.com [*.*.*.*] did not issue
> MAIL/EXPN/VRFY/ETRN during connection to MTA
> Mar 27 06:31:29 hostname sendmail[752]: NOQUEUE:
> host*-*-*-*.in-addr.btopenworld.com [*.*.*.*] did not issue
> MAIL/EXPN/VRFY/ETRN during connection to MTA
> Mar 27 06:32:39 hostname sendmail[792]: NOQUEUE:
> host*-*-*-*.in-addr.btopenworld.com [*.*.*.*] did not issue
> MAIL/EXPN/VRFY/ETRN during connection to MTA
> Mar 27 06:33:49 hostname sendmail[834]: NOQUEUE:
> host*-*-*-*.in-addr.btopenworld.com [*.*.*.*] did not issue
> MAIL/EXPN/VRFY/ETRN during connection to MTA
> Mar 27 06:34:59 hostname sendmail[896]: NOQUEUE:
> host*-*-*-*.in-addr.btopenworld.com [*.*.*.*] did not issue
> MAIL/EXPN/VRFY/ETRN during connection to MTA
> .... continuous ......

> they are happening every 1 min and 10 seconds roughly and as i said been
> going on for about 10-12 hours. all from the same host...
> Ive sniffed the traffic and captured the whole session. its quite short and
> i have recreated it from another machine below ....

> -- Start Session --
> Connected to *.*.*.*.
> Escape character is '^]'.
> 220 hostname.net ESMTP Sendmail 8.10.2/8.10.2; Wed, 27 Mar 2002 09:02:13 GMT
> EHLO michael
> 250-hostname.net Hello **.*****.com [*.*.*.*], pleased to meet you
> 250-ENHANCEDSTATUSCODES
> 250-8BITMIME
> 250-SIZE 2097152
> 250-DSN
> 250-ONEX
> 250-ETRN
> 250-XUSR
> 250-AUTH PLAIN
> 250 HELP

> 500 5.5.1 Command unrecognized: ""
> AUTH PLAIN
> 334 =
> AHZpYXVrAA==
> 500 5.7.0 authentication failed
> QUIT
> 221 2.0.0 hostname.net closing connection
> -- End Session --

> I dont understand what this persons trying to do as its using the same
> password each time and using
> this same michael hostname. so it appears not to be a Bruteforce.

> Is this just a small pointless automated DOS or coudl it be something more
> worrying ? could anyone shed
> any light on this or offer any advice. I know i coudl just add to hosts.deny
> but im just trying to
> figure out why its going on and prevent it happening again. any suggestions
> / linkage would be great.

> many thanks.

> fragga

> ps i made a post on here before but it got returned ... dunno why :(


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