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tshark extract from 5 gig trace

asked 2020-02-29 16:35:45 +0000

quest4answer gravatar image

hello: I have 5 gig trace file and i need to extract all the streams which has below server name on tls handshake. is there a tshark command to create a new tracefile with only those streams or is there any other way to accomplish?

tls.handshake.extensions_server_name == "".


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"all the streams" does this mean individual TCP streams - all packets with the same number?

Could you make a pass through to collect those values based on the handshake string you showed then in a loop extract packets with the number as a filter?

Chuckc gravatar imageChuckc ( 2020-02-29 17:46:19 +0000 )edit

@SYN-bit is the tshark master:
SF19EU 07 - Solving (SharkFest) packet challenges using tshark alone (Sake Blok)

@NetDetect shrinking large files
SF19US - 08 Taking a bite out of 100GB files (Betty DuBois)

Chuckc gravatar imageChuckc ( 2020-02-29 18:32:06 +0000 )edit

I meant all the packets with, which has server name =="". when i displayed with that filter there are 40 packets came up with client hello. basically i need to export all the packets comes in client hello conversation filters for all the 40 client hello. hoepfully thats clear now thanks

quest4answer gravatar imagequest4answer ( 2020-02-29 23:55:27 +0000 )edit

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answered 2020-03-24 08:00:31 +0000

SYN-bit gravatar image

In a bash-like shell you can do:

tshark -r <file> -w <new-file> -Y " in { $(tshark -r <file> -Y tls.handshake.extensions_server_name=="" -T fields -e | sort | uniq | xargs)"

Where tshark -r <file> -Y tls.handshake.extensions_server_name=="" -T fields -e lists all the numbers of the client hellos that contain the requested SNI.

Then ... | sort | uniq | xargs creates a list of unique numbers

Then " in { $(<command>) }" creates a display filter based on the output of the previous command.

And of course tshark -r <file> -w <new-file> - Y <filter> saves a new pcap file with the filtered data.

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Asked: 2020-02-29 16:35:45 +0000

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Last updated: Mar 24 '20