I'm trying to identify trouble users on our network. ntop identifies high traffic and high connection users, but malware doesn't always need high bandwidth to really mess things up. So I am trying to do offline analysis with snort (don't want to burden the router with inline analysis of 20 Mbps traffic). Apparently snort provides a -r option for this purpose, but I can't get the analysis to run.
The analysis system is gentoo, amd64, in case that makes any difference. I've already used oinkmaster to download the latest IDS signatures. But when I try to run snort, I keep getting the following error:
% snort -V
,,_ -*> Snort! <*-
o" )~ Version 2.9.0.3 IPv6 GRE (Build 98) x86_64-linux
'''' By Martin Roesch & The Snort Team: http://www.snort.org/snort/snort-team
Copyright (C) 1998-2010 Sourcefire, Inc., et al.
Using libpcap version 1.1.1
Using PCRE version: 8.11 2010-12-10
Using ZLIB version: 1.2.5
%> snort -v -r jan21-for-snort.cap -c /etc/snort/snort.conf -l ~/snortlog/
(snip)
273 out of 1024 flowbits in use.
[ Port Based Pattern Matching Memory ]
+- [ Aho-Corasick Summary ] -------------------------------------
| Storage Format : Full-Q
| Finite Automaton : DFA
| Alphabet Size : 256 Chars
| Sizeof State : Variable (1,2,4 bytes)
| Instances : 314
| 1 byte states : 304
| 2 byte states : 10
| 4 byte states : 0
| Characters : 69371
| States : 58631
| Transitions : 3471623
| State Density : 23.1%
| Patterns : 3020
| Match States : 2934
| Memory (MB) : 29.66
| Patterns : 0.36
| Match Lists : 0.77
| DFA
| 1 byte states : 1.37
| 2 byte states : 26.59
| 4 byte states : 0.00
+----------------------------------------------------------------
[ Number of patterns truncated to 20 bytes: 563 ]
ERROR: Can't find pcap DAQ!
Fatal Error, Quitting..
net-libs/daq is installed, but I don't even want to capture traffic, I just want to process the capture file.
What configuration options should I be setting/unsetting in order to do offline analysis instead of real-time capture?
