Snort mailing list archives
asynchronous_link was snort sees no fragmented attack
From: Holger.Woehle () arcor net
Date: Tue, 13 Aug 2002 14:52:11 +0100
Holger.Woehle () arcor net writes: ...i switched on the asynchronous_link but it doesn't change anything. I noticed that i cannot use the "flow" option even with asynchronous link... Snort 1.9 does not recognize the alarms declared with
"flow:to_server,established" .
Chris Green <cmg () sourcefire com> writes: Well, in 1.9 w/ a 1.9 ruleset, you should turn on preprocessor stream4: asynchronous_link you are running into the state machines actually caring about the state of a TCP session which it can't ascertain w/o haivng both sides of the conversation. This is not related to fragmentation. -- Chris Green <cmg () sourcefire com> A good pun is its own reword.
Holger.Woehle () arcor net writes: echo "GET /aaaaaaa/aaa/aaaaa/aaaaaaaa/aaaaaaa/bcc/bin/ps" | nc The Sensor listens behind a Shomiti Ethernet TAP. May this be the problem ? The Sensor only catches the "incoming" traffic. I do not want the answers from the machines. Am i wrong with that ? Does snort neeed the outgoing traffic for defrag ?
i switched to snort 1.9 beta 2 and connected the sensor to both ends of the TAP using device bond0. Now i see all alerts! But i don't want to inspect all outgoing traffic! Do i need to abjust something according to use preprozessor stream4:asynchronous_link ? Do i need to configure preprozessor stream4_reassembly: client_only or something else ? cu Holger ------------------------------------------------------- This sf.net email is sponsored by: Dice - The leading online job board for high-tech professionals. Search and apply for tech jobs today! http://seeker.dice.com/seeker.epl?rel_code=31 _______________________________________________ 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
Current thread:
- asynchronous_link was snort sees no fragmented attack Holger . Woehle (Aug 13)
- Re: asynchronous_link was snort sees no fragmented attack Chris Green (Aug 13)