Snort mailing list archives
RE: RE: How to Triggering Windows Exploits?
From: "Alan" <ids () san rr com>
Date: Tue, 25 May 2004 23:43:41 -0700
Rob, Thank you for your reply! This is what I was looking for. I apologize for my noobness on rules. I haven't gotten too writing rules yet but hopefully I'll learn that in the future. A quick question. Concerning the two included generic rules you include on the bottom of the email...because those rules aren't looking for any particular signature within the packet any packets either establishing a session on port 445 in the case of the first rule or any packet hitting port 445 on the second rule would trigger an alert correct? Also what is the reasoning in including flow: to_server, established in rules? Thanks in advance! Alan I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. Linus (torvalds () kruuna helsinki fi) Date: 1991-08-25 23:12:08 PST -----Original Message----- From: Rob Schrack [mailto:rob_schrack () urmc rochester edu] Sent: Tuesday, May 25, 2004 4:07 PM To: ids () san rr com Subject: Re: RE: [Snort-users] How to Triggering Windows Exploits? It really depends on how a particular rule is written. Take the following rules: alert udp $EXTERNAL_NET any -> $HOME_NET 135 (msg:"NETBIOS DCERPC Messenger Service buffer overflow attempt"; content:"|04 00|"; offset:0; depth:2; byte_test:1,>,15,2,relative; byte_jump:4,86,little,align,relative; byte_jump: 4,8,little,align,relative; byte_test:4,>,1024,0,little,relative; reference:url,www.microsoft.com/technet/security/bulletin/MS03-043.mspx; reference:bugtraq,8826; reference:cve,CAN-2003-0717; classtype:attempted-admin; sid:225 7; rev:2;) alert tcp $EXTERNAL_NET any -> $HOME_NET 445 (msg:"NETBIOS SMB-DS DCERPC Messenger Service buffer overflow attempt"; flow:to_server,established; content:"|FF|SMB|25|"; nocase; offset:4; depth:5; content:"|26 00|"; distance:56; within:2; content:"|5c 00|P|00|I|00|P|00|E|00 5c 00|"; nocase; distance:5; within:12; content:"|04 00|"; distance:0; within:2; byte_test:1,>,15,2,relative; byte_jump:4,86,little,align,relative; byte_jump:4,8,little,align,relative; byte_test:4,>,1024,0,little,relative; reference:url,www.microsoft.com/technet/security/bulletin/MS03-043.mspx; reference:bugtraq,8826; reference:cve,CAN-2003-0717; classtype:attempted-admin; sid:2258; rev:3;) The first is a UDP rule. Basically if you allow port 135 into your network (or past the snort sensor), you should see an alert if a matching packet flies by. The 2nd is a TCP rule. Notice the "flow" options just past the name of the rule: "flow: to_server,established". The 'established' option will only trigger an alert on a packet that is part of an established session on port 445. If you don't have a box listening on 445/tcp, there should never be an established session, and you should never see an alert triggered. If you get more generic, alert tcp $EXTERNAL_NET any -> $HOME_NET 445 (msg:"NETBIOS SMB-DS DCERPC Messenger Service buffer overflow attempt"; flow:to_server,established;) alert tcp $EXTERNAL_NET any -> $HOME_NET 445 (msg:"NETBIOS SMB-DS DCERPC Messenger Service buffer overflow attempt";) The first would trigger on any established session on port 445/tcp, regardless of what that service actually is. The second would trigger on ANY attempt on 445/tcp, like a SYN scan. Hope that helps. Rob ----- Original Message ----- From: <ids () san rr com> To: "Joshua Berry" <jberry () PENSON COM> Cc: <snort-users () lists sourceforge net> Sent: Tuesday, May 25, 2004 6:30 PM Subject: Re: RE: [Snort-users] How to Triggering Windows Exploits?
Hi Joshua, Your answer is a little bit different from what I was asking. Let me
elaborate a little. Are the rules written in a way that requires a targeted computer have to respond to an attack or something of that nature for Snort to issue an alert. I have yet to see my Snort sensor alert me to any MS exploits (various network worms such as Sasser, blaster...etc) . I assumed the reason for this was because there are no Windows PC connected to the network Snort is sensing on. Another test I ran to see if Snort would issue an alert was the Cisco exploits. I do not have any Cisco devices on my network but I attempted to trigger an alert my hitting an IP on the protected network with the PERL script. No alerts. Do I have to have the appropriate Cisco deivce to trigger the alert? Just a side note I'm using the most current rules for Snort (inluding the rules to detect the Cisco exploits) for testing and information gathering.
Any help on this I would greatly appreciate! Alan ----- Original Message ----- From: Joshua Berry <jberry () PENSON COM> Date: Tuesday, May 25, 2004 1:39 pm Subject: RE: [Snort-users] How to Triggering Windows Exploits?Snort will not verify OS or Services running on the target machine unless you patch it with something like the Attack Verification patch that uses Nessus to verify actual vulnerabilities of the target. -----Original Message----- From: snort-users-admin () lists sourceforge net [snort-users-admin () lists sourceforge net] On Behalf Of ids () san rr com Sent: Tuesday, May 25, 2004 2:46 PM To: snort-users () lists sourceforge net Subject: [Snort-users] How to Triggering Windows Exploits? Hi everyone- I have a simple question. Is it true that some Snort alerts are only triggered if the target computer is vulnerable to that attack? To be a little more specific... if an attacks targets an exploit in Windows 2000 and I only have Linux running in my network will Snort alert me to thoseWindows attacks? The reason I ask is because I have a Snort sensordetecting detecting attacks against a Linux box running Apache. I noticed that the only attacks I detect are SQL, HTTP and Linux related.About a week ago for a brief time an associate put a Windows 2k box off of the hub and I started to get hit with these Alerts I had never seen before (MS Exploits). I want to capture more data on the amount of exploits attacks on Windows and was wondering for me to gather that data would I have to have a Windows computer on the network Snort is sensing?Thanks in advance! Alan ------------------------------------------------------- This SF.Net email is sponsored by: Oracle 10g Get certified on the hottest thing ever to hit the market... Oracle 10g. Take an Oracle 10g class now, and we'll give you the exam FREE. http://ads.osdn.com/?ad_id=3149&alloc_id=8166&op=click _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users------------------------------------------------------- This SF.Net email is sponsored by: Oracle 10g Get certified on the hottest thing ever to hit the market... Oracle 10g. Take an Oracle 10g class now, and we'll give you the exam FREE. http://ads.osdn.com/?ad_id=3149&alloc_id=8166&op=click _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
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Current thread:
- How to Triggering Windows Exploits? ids (May 25)
- <Possible follow-ups>
- RE: How to Triggering Windows Exploits? Joshua Berry (May 25)
- Re: RE: How to Triggering Windows Exploits? ids (May 25)
- Re: How to Triggering Windows Exploits? James Riden (May 25)
- RE: How to Triggering Windows Exploits? Alan (May 26)
- Re: How to Triggering Windows Exploits? James Riden (May 25)
- RE: RE: How to Triggering Windows Exploits? Alan (May 26)
- RE: RE: How to Triggering Windows Exploits? Alan (May 26)
- Re: RE: How to Triggering Windows Exploits? Hendo (May 26)