Snort mailing list archives

RE: CodeRed Observations.


From: "John York" <YorkJ () brcc edu>
Date: Thu, 13 Mar 2003 13:58:54 -0500

Here's what I saw in yesterday's logs.  I've been assuming that hits on
cmd.exe and .ida are codered/Nimda scans.  I looked at the rules for
both of these and both have flow:to_server,established so I'm assuming
the Snort pre-processors must have seen a complete handshake before the
rules fired.  I haven't made any special rules for this, so I doubt I'd
see any hits without an established connection.
Thanks
John

03/13-14:25:54.526549   WEB-IIS cmd.exe access  TCP     164.125.128.129
4243    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11        0x5EA
***A****        0x3BCA6552      0x650253D9              0x16D0  50
16      46551   448     20
03/13-14:25:54.526087   WEB-IIS ISAPI .ida attempt      TCP
164.125.128.129 4243    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11
0x5EA   ***A****        0x3BCA5F9E      0x650253D9              0x4020
52      0       32154   217     20
03/13-02:06:19.832951   WEB-IIS cmd.exe access  TCP     164.125.61.214
1146    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11        0x5EA
***A****        0xE48D8B3       0xC0E6DDBA              0x4020  52
0       32160   217     20
03/13-02:06:19.831720   WEB-IIS ISAPI .ida attempt      TCP
164.125.61.214  1146    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11
0x5EA   ***A****        0xE48D2FF       0xC0E6DDBA
63      0       0       121     20
03/13-03:13:15.505757   WEB-IIS cmd.exe access  TCP     164.77.209.252
1983    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11        0x5EA
***A****        0xCDC7E3C3      0xFF6B24FD                      127
0       22628   105     20
03/13-03:13:15.336757   WEB-IIS ISAPI .ida attempt      TCP
164.77.209.252  1983    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11
0x5EA   ***A****        0xCDC7DE0F      0xFF6B24FD              0x16D0
52      0       61486   160     20
03/13-20:59:15.896767   WEB-IIS cmd.exe access  TCP     164.77.218.214
3505    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11        0x5BC
***A****        0xEE901D89      0xCBF5F076              0x4000  109
0       10931   48      20
03/13-20:59:15.812044   WEB-IIS ISAPI .ida attempt      TCP
164.77.218.214  3505    x.x.x.x 80      0:8:21:9C:FD:20 0:90:27:4D:56:11
0x5BC   ***A****        0xEE901803      0xCBF5F076              0x4000
109     0       11147   48      20

alert tcp $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"WEB-IIS
ISAPI .ida attempt"; flow:to_server,established; uricontent:".ida?";
nocase; reference:arachnids,552; classtype:web-application-attack;
reference:bugtraq,1065; reference:cve,CAN-2000-0071; sid:1243; rev:8;)

alert tcp $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"WEB-IIS
cmd.exe access"; flow:to_server,established; content:"cmd.exe"; nocase;
classtype:web-application-attack; sid:1002;  rev:5;)

John York
Network Engineer
Blue Ridge Community College
P.O. Box 80/One College Lane
Weyers Cave, VA 24486
540.453.2255

-----Original Message-----
From: larosa, vjay [mailto:larosa_vjay () emc com]
Sent: Wednesday, March 12, 2003 4:13 PM
To: John York
Cc: snort-users () lists sourceforge net
Subject: RE: [Snort-users] CodeRed Observations.

But are you seeing the originating source of the attack
establishing a TCP session (Three way handshake) with
your webservers? I'm not. It is almost like a stick or
snort attack with codered packets.

vjl

-----Original Message-----
From: John York [mailto:YorkJ () brcc edu]
Sent: Wednesday, March 12, 2003 3:13 PM
To: larosa, vjay
Cc: snort-users () lists sourceforge net
Subject: RE: [Snort-users] CodeRed Observations.


The main difference I'm seeing is that the new CodeRed's send just a
few
attempts to my web servers (cmd.exe, ida, etc) instead of pounding
them
with a hundred or so like they did before.


John York
Network Engineer
Blue Ridge Community College
P.O. Box 80/One College Lane
Weyers Cave, VA 24486
540.453.2255

-----Original Message-----
From: snort-users-admin () lists sourceforge net [mailto:snort-users-
admin () lists sourceforge net] On Behalf Of larosa, vjay
Sent: Wednesday, March 12, 2003 12:04 PM
To: 'intrusions () incidents org'
Cc: 'snort-users () lists sourceforge net';
'focus-ids () securityfocus com'
Subject: [Snort-users] CodeRed Observations.

Hello,

I have been watching this recent spike in CodeRed activity and one
thing I
am noticing
is the lack of TCP session establishment. I am seeing common get
strings
like this showing
up at my firewalls without ever establishing a TCP three way
handshake. I
have seen several
hundred packets with in the last two days similar to this at my
firewalls.

47 45 54 20 2F 64 65 66 61 75 6C 74 2E 69 64 61  GET /default.ida
3F 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58  ?XXXXXXXXXXXXXXX
58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58  XXXXXXXXXXXXXXXX
58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58  XXXXXXXXXXXXXXXX
58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58  XXXXXXXXXXXXXXXX


Snip--------------------------------------------------------------------
--
--
----------------------------------------------------

I find it awfully strange that there is no handshake (not even a
single
SYN
to try and establish
a session) but these packets show up anyway. I also am not seeing an
increase of port 80
scans in my firewall logs or with any of my IDS sensors. Is anybody
else
out
there seeing the
same things we are?

Thanks!

vjl

V.Jay LaRosa                           EMC Corporation
Information Security                  4400 Computer Dr.
(508)898-7433 office                  Westboro, MA 01580
(508)353-1348 cell                     www.emc.com
888-799-9750 pager                   larosa_vjay () emc com





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