IDS mailing list archives
Re: bittorrent file transfer - rate limit
From: "Ravi Chunduru" <ravi.is.chunduru () gmail com>
Date: Tue, 9 Oct 2007 23:30:19 -0700
okay. Thank you for detailed explanation. Ravi On 10/9/07, Srinivasa Addepalli <srao () intoto com> wrote:
Hi, Older versions of Bit Torrent clients use TCP based transfer for downloading and uploading pieces. Later versions of clients support multiple methods for data transfer. Web seeding is one method which we see commonly. We also see Azureus client using UDP based data transfer. In addition, if peers support cryptography, then the connections (TCP or UDP) are encrypted. It is difficult to detect encrypted connections using typical pattern matching. First two packets of the connection exchange DH pairs to get symmetric key. This symmetric key is used to encrypt rest of stream. First two packets are even padded with random data of random length to avoid detection by any traffic enforcers. This is done very cleverly and it had been very successful. We believe that Traffic Heuristics combined with some intelligence of tracker connections is one way to detect these encrypted connections. By the way, IntruPro-IPS has signatures for detecting 'web seeding' and 'UDP' based data transfer connections in addition to TCP based connections. These signatures were added recently and you may like to get latest version of signature set. Srini -----Original Message----- From: listbounce () securityfocus com [mailto:listbounce () securityfocus com] On Behalf Of Ravi Chunduru Sent: Sunday, October 07, 2007 9:27 AM To: focus-ids () securityfocus com Subject: bittorrent file transfer - rate limit i am trying to use IntroPro-IPS to limit bittorrent traffic to 20% of my bandwidth. it is able to detect file transfer traffic in many cases using rules given as part of product distribution. if i use bittorrent (downloaded from www.bittorrent.com) i could see that this p2p traffic is not exceeding 20% limit (100kbps). but if i use other client application such as azureus or uTorrent, i find that bittorrent data traffic is not recognized for some torrents. this product has facility to add new rules to detect application traffic. i tried to add new rules with patterns from bleedingthreats and l7 filters and results are same. does anybody have right patterns to detect all kinds of bittorrent file transfer connections? thanks Ravi ------------------------------------------------------------------------ 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.coresecurity.com/index.php5?module=Form&action=impact&campaign=in tro_sfw to learn more. ------------------------------------------------------------------------ ******************************************************************************** This email message (including any attachments) is for the sole use of the intended recipient(s) and may contain confidential, proprietary and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please immediately notify the sender by reply email and destroy all copies of the original message. Thank you. Intoto Inc.
------------------------------------------------------------------------ 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.coresecurity.com/index.php5?module=Form&action=impact&campaign=intro_sfw to learn more. ------------------------------------------------------------------------
Current thread:
- bittorrent file transfer - rate limit Ravi Chunduru (Oct 09)
- RE: bittorrent file transfer - rate limit Srinivasa Addepalli (Oct 10)
- Re: bittorrent file transfer - rate limit Ravi Chunduru (Oct 10)
- Re: bittorrent file transfer - rate limit Ravi Chunduru (Oct 19)
- RE: bittorrent file transfer - rate limit Srinivasa Addepalli (Oct 19)
- RE: bittorrent file transfer - rate limit Srinivasa Addepalli (Oct 10)