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RE: Strange logon attempts to Win2k server
From: "Sean" <sean () comnet com>
Date: Wed, 24 Sep 2003 21:50:37 -0600


Chris,

This may be related to what I had found on one of my clients servers
recently.  Their server was being overloaded by spam that was being sent out
through Exchange.  I knew that they were not running an open relay, and
quickly ran down the possibilities as to what could have been happening.
After turning up all the logging, my suspicions were confirmed.  The
spammers had started attempting to authenticate to the Exchange server for
permission to send mail.  They had guessed the passwords for both the
administrator and backup accounts (yes, they were very poor passwords), and
were sending massive amounts of spam through the Exchange server. I imagine
the attempts that you are seeing are this same type of attempted access.

I guess now spammers are resulting to felony network intrusion to spread
their pee-pee grow big pills. :)


-----Original Message-----
From: Chris Harrington [mailto:cmh () nmi net]
Sent: Thursday, September 11, 2003 10:09 AM
To: pen-test () securityfocus com
Subject: Strange logon attempts to Win2k server


All,

A customer notified us that someone / something tried to log into one of
their servers repeatedly but failed. It appears to be some sort of
script since it tried 6 usernames with 23 passwords in under 2 minutes.
The event log is a typical 529 event ID. The logon type was 3 (network)
and the logon process was advapi. I generally see this when someone
tries to log in to IIS using cleartext authentication. There is no
evidence in the w3svc logs of these attempts. There were no successful
logins using that logon process.

This server is an Exchange server with port 25 accessible from the
Internet. I have verified this is the only port open by scan and
firewall rules.

1. Can anyone access the advapi (or any domain login process) over port
25 on an Exchange server? I did not think that SMTP AUTH could do that..

2. What other common programs use the advapi call for authentication?

The usernames that were tried are webmaster, admin, root, test, master,
web. Each one was tried in that order with 23 passwords, all failed.

3. Does anyone know what script / app / virus / worm that could be?

Any insights??

Thanks,

--Chris

-----Original Message-----
From: Bartholomew, Brian J [mailto:BartholomewBJ () state gov]
Sent: Monday, July 21, 2003 10:48 AM
To: 'Ian Chilvers'; pen-test () securityfocus com
Subject: RE: V/Scan for Wireless LANs


        I have successfully cracked 40 and 104 bit WEP keys with reinj.c
and Airsnort or Kismet.  Just use Airsnort or Kismet to listen and store
the "interesting" traffic, and reinj.c to create it.  One usually needs
between 100 MB to 1 GB of  traffic to crack the key, but once the data
is captured, the key cracks in a matter of seconds.

        There is a good paper that describes the weak implementation of
initialization vectors entitled "Weaknesses in the Key Scheduling
Algorithm of RC4" by Scott Fluhrer, Itsik Mantin, and Adi Shamir.  I
suggest reading it.

        I mentioned Kismet above.  It is one of the best tools out there
for WLAN testing.  It allows you to perform a variety of things to the
AP such as spoofing, disassociations, capture traffic, sniff out
"hidden" APs, etc. It is all around a better tool to use than
NetStumbler since it detects APs passively, instead of broadcasting
everywhere.  It even detects other NetStumbler clients.

        The suggestion to brute force the key is not a good idea since,
as one person already pointed out, it would take a very long time to BF
it.  It could be done I guess, but by the time the key is cracked, they
would have
probably already changed it.

        Personally I think the best way of attack is to use some sort of
man in the middle attack.  If you are able to disassociate the clients
from that AP and have them re-associate with you, you are golden :).

Brian J. Bartholomew
U.S. Dept of State, Bureau of Diplomatic Security
Computer Incident Response Team
(202)663-2304


-----Original Message-----
From: Ian Chilvers [mailto:Ian.Chilvers () prolateral com]
Sent: Friday, July 18, 2003 12:45 PM
To: pen-test () securityfocus com
Subject: V/Scan for Wireless LANs


Hi all

We've been asked to perform a vulnerability assessment for a company
that has a Wireless LAN.  The W/LAN is running WEP with a random key
generated, rather than a dictionary word.

Are there any tools out there that can brute force a WEP.

Take this example.  A person parks the car in the car park and sniffs
the air waves with a product like NetStumbler.  He discovers the W/LAN
but with WEP.

Is there a tool he can use to discover the WEP key (possible by brute
force)

If there isn't such a tool, how does this sound for an idea.

Run a app that starts at binary 0's and counts upto 128bits of 1's For
each sequence listen to see if there are any sensible packets or even
send out a DHCP discover request to see if you get a reply.  This would
then possibly give you the WEP key.

Any comments

Ian....



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