Hi,
It's easy if you know the protocol to be converted. Only use a C
structure and write the corresponding snort rules value into respective
position. Empty positions can be filled with fake values, because if it
was important would be in rule. It's irrelevant.
Example:
alert tcp $EXTERNAL_NET 80 -> $HOME_NET 1054 (msg:"BACKDOOR ACKcmdC trojan
scan"; ack:101058054; flags:A,12; seq:101058054; flow:stateless;
reference:arachnids,445; classtype:misc-activity; sid:106; rev:8;)
Fill TCP destination port with 1054, source port with 80, the tcp ack
with 101058054, on ack flag, seq with 101058054.
Fill the others fields with fake values. dst IP and src IP can be filled
with 192.168.0.1, by example.
Some ways exist to capture real packets. Tcpdump is a good way, but
capture only tcp.
I'm using libpcap, a C library, and I had good results.
[]'s
Israel
Sanjay Rawat wrote:
Hi Israel:
ok. it sounds well. but why do you want snort rules to be converted
into corresponding network packets? i may be missing something here.
it is also possible to take the tcpdump files corresponding to attacks
and use TcpReplay tool to inject those packets. then see which snort
rules get triggered. in this way, you will come to know the traffic
corresponding to (required) rules. Am I sounding some sense?
regards
Sanjay
At 07:43 PM 8/25/2005, Israel wrote:
Hi,
In the beginning, I will use some known attacks logs, generated by
known scans, how nmap, fingerprint and analyzing the TCP packet
content. The strings in content are good attack indication.
"wget%20" , "/bin/sh" are common strings used in server pages attacks.
Common signatures can be found in snort rules. We can build malicious
network packets to use in repository.
alert tcp $EXTERNAL_NET any -> $HOME_NET 22 (msg:"EXPLOIT ssh CRC32
overflow /bin/sh"; flow:to_server,established; content:"/bin/sh";
reference:bugtraq,2347; reference:cve,2001-0144;
reference:cve,2001-0572; classtype:shellcode-detect; sid:1324; rev:6;)
alert tcp $EXTERNAL_NET any -> $HOME_NET 22 (msg:"EXPLOIT ssh CRC32
overflow NOOP"; flow:to_server,established; content:"|90 90 90 90 90
90 90 90 90 90 90 90 90 90 90 90|"; reference:bugtraq,2347;
reference:cve,2001-0144; reference:cve,2001-0572;
classtype:shellcode-detect; sid:1326; rev:6;)
alert tcp $EXTERNAL_NET any -> $HOME_NET 22 (msg:"EXPLOIT ssh CRC32
overflow"; flow:to_server,established; content:"|00 01|W|00 00 00
18|"; depth:7; content:"|FF FF FF FF 00 00|"; depth:14; offset:8;
reference:bugtraq,2347; reference:cve,2001-0144;
reference:cve,2001-0572; classtype:shellcode-detect; sid:1327; rev:7;)
It's some examples found in exploit.rules file.
Currently, I need somebody make a module that converts rules of snort
to real network packets.
=)
Icya
Sanjay Rawat wrote:
Hi Israel:
This is Sanjay. Its nice to hear about your project, based on CBR. i
will be happy to participate in discussion on points/problems, which
you may face during the project. to my understanding, the main issue
in CBR is to represent the known cases (in your case, attacks) in an
effective manner. I find good theoretical papers, but less real-life
implementations of CBR. Most of the applications are from medical
side. There are couple of papers, suggesting the use of CBR in IDS
(i dont remember the references at present, probably some googling
will do that). which attack repository, are you going to use- DARPA?
best wishes and regards
Sanjay
At 08:13 PM 8/24/2005, Israel wrote:
Hello,
I'm developing a IDS project in my computer science graduation.
It will be use Case-Based Reasoning and handle a repository with
the malicious network log to generate responses.
The libpcap is used to capture a network trafic.
Have you suggestions to implementation?
The software is under GPL license and I would like to invite
interested peoples to program.
Thanx
Israel Rocha
------------------------------------------------------------------------
Test Your IDS
Is your IDS deployed correctly?
Find out quickly and easily by testing it with real-world attacks
from CORE IMPACT.
Go to
http://www.securityfocus.com/sponsor/CoreSecurity_focus-ids_040708
to learn more.
------------------------------------------------------------------------
Sanjay Rawat
Senior Software Engineer
INTOTO Software (India) Private Limited
Uma Plaza, Above HSBC Bank, Nagarjuna Hills
PunjaGutta,Hyderabad 500082 | India
Office: + 91 40 23358927/28 Extn 422
Website : www.intoto.com
Homepage: http://sanjay-rawat.tripod.com
------------------------------------------------------------------------
Test Your IDS
Is your IDS deployed correctly?
Find out quickly and easily by testing it with real-world attacks
from CORE IMPACT.
Go to
http://www.securityfocus.com/sponsor/CoreSecurity_focus-ids_040708 to
learn more.
------------------------------------------------------------------------
Sanjay Rawat
Senior Software Engineer
INTOTO Software (India) Private Limited
Uma Plaza, Above HSBC Bank, Nagarjuna Hills
PunjaGutta,Hyderabad 500082 | India
Office: + 91 40 23358927/28 Extn 422
Website : www.intoto.com
Homepage: http://sanjay-rawat.tripod.com
------------------------------------------------------------------------
Test Your IDS
Is your IDS deployed correctly?
Find out quickly and easily by testing it
with real-world attacks from CORE IMPACT.
Go to http://www.securityfocus.com/sponsor/CoreSecurity_focus-ids_040708
to learn more.
------------------------------------------------------------------------
