Radium identify TLS handshakes?
"James A. Robinson" <[email protected]> Thu, 15 Mar 2018 22:42:23 +0000
| Newsgroups | gmane.network.argus |
|---|---|
| Message-ID | <CAPd04b7mdBHccgY6h4sLJB88ke=c2Wj8zJKBGmMiULzU2g+-qA@mail.gmail.com> |
Hi, I've a need to identify hosts initiating outgoing TLS connections. It's a lot of hosts that I need to examine (around a thousand), and I'm worried about the amount of disk that will consume if I just gather the argus data from all of them. Is there a way to filter the radium data such that I can just capture the minimal fact of "host X initiated a TLS connection to host Y"? Looking over the man page I saw there is a RADIUM_FILTER option that can take the same sort of filtering parameters as tcpdump. On stackoverflow there is a discussion about capturing just the initial part of a TLS conversation: https://stackoverflow.com/questions/39624745/capture-only-ssl-handshake-with-tcpdump If I run tcpdump and apply the following expression: tcp port 443 and (tcp[((tcp[12] & 0xf0) >> 2)] = 0x16) It seems to do what I want, it shows a bit of activity for each outgoing TLS connection I make, rather than all the packets. Is there a way to use something similar to this expression in RADIUM_FILTER to capture just the initial handshake? I tried adding it wholesale RADIUM_FILTER="tcp port 443 and (tcp[((tcp[12] & 0xf0) >> 2)] = 0x16)" but radium didn't register any activity, whereas I do see activity when I filter on the simpler expression just looking at the port: RADIUM_FILTER="tcp port 443" This is on a pair of Linux systems running argus and radium 3.0-8. Jim