Re: Logging Packets with Snort

[Johnny Venter <Johnny.Venter () zoho com>]

Hi Jeremy, thanks for the quick response and yes, I need more help :)

When I issue: 

openfpc-client -a status

The oldest packet is: 1380905610 (Fri Oct  4 12:53:30 2013)

The packet request in my previous email was requested today.  

Here's some more information on my setup:  I have a snort sensor with Barnyard2, MySQL and with openfpc installed and 
capturing packets--I think they reference this as running in "slave" mode.  I have another server that runs Snorby and 
connects to the MySQL database on the snort sensor.  I request packets from the Snorby server which in turn connects to 
the snort sensor for packet requests.

Any other ideas was to why I'm getting 24 byte packets?
While I do like the full packet capture so I can detect the start of an intrusion, can I query the unified2 file 
similar to what Sourcefire does?  

Thanks.


On Oct 25, 2013, at 2:52 PM, Jeremy Hoel <jthoel () gmail com> wrote:

> The interface you are talking about and using is Snorby; it's a gui for looking at snort alerts.  Snort itelf does 
> not capture full packets, just the bits that cause the event (like you see in SourceFire).  Snorby has a plug-n for 
> the a tool called OpenFPC (which is what you see in your logs) that connects back to an OpenFPC client/server to get 
> the pcap data, but you have to run openfpc on the sensor and set it up.
>
> We've found that the 'extract packets' part doesn't work great due to the way that OpenFPC does client/server comms 
> over many devices.  But, we do run OpenFPC, do the full packet captures and pull the packets ourselves with a script 
> to the sensor that we want the data from.
>
> The errors you are showing could be because the pcap data isn't there anymore (how far back do your openfpc captures 
> go?)
>
> I hope that helps clarify some bits and if you need more help, let me know.
>
>
>
>
> On Fri, Oct 25, 2013 at 6:45 PM, Johnny Venter <Johnny.Venter () zoho com> wrote:
> Having some performance issues with my Snort sensor that has OpenFPC installed.
>
> Not sure if this is the right place for this question, but here goes:
>
> I have a sensor that monitors the Internet traffic.  The interface is 1GB.  When I try to download packet captures 
> (from Snorby) most of the time it takes a while and then downloads a packet that is 24 bytes.  When I open this pcap 
> in Wireshark or tcpdump, it only displays one line: link-type EN10MB (Ethernet)
>
> When I click on the "Packet Capture Options" in Snorby:
>
> <Screen Shot 2013-10-25 at 2.37.55 PM.png>
>
> I watch the syslog from my snort sensor and here is the output:
>
> Oct 25 14:34:15 snort_s OpenfpcQ[1035]: snort_s COMMS: Accepted new connection from 127.0.0.1
> Oct 25 14:34:15 snort_s OpenfpcQ[1035]: snort_s DECODE: User netp-user assigned RID: 0 for action fetch. Comment: 0 
> Filetype : PCAP
> Oct 25 14:34:15 snort_s OpenfpcQ[1035]: snort_s COMMS: 127.0.0.1: RID: 15 Fetch Request OK -> WAIT!
> Oct 25 14:34:15 snort_s OpenfpcQ[1035]: snort_s NODE: Request: 15 User: netp-user Action: fetch BPF: host 
> 192.168.216.175 and host 192.168.216.77 
> Oct 25 14:34:42 snort_s OpenfpcQ[1035]: snort_s NODE: Request: 15 User: netp-user Result: 1382726055-15.pcap, 24, 
> ab487d36057d446b6a8b72091da72f23
> Oct 25 14:34:42 snort_s OpenfpcQ[1035]: snort_s COMMS: 15 127.0.0.1 Sending File:/tmp/1382726055-15.pcap MD5: 
> ab487d36057d446b6a8b72091da72f23
> Oct 25 14:34:42 snort_s OpenfpcQ[1035]: snort_s COMMS: Uploaded 1 x 1KB chunks
>
> So it's really a hit or miss with my packet capture.  Does anyone have any idea why this happens? 
>
> Also, in the commercial version of Snort (Sourcefire), it *seems* to capture just the packet the generated the 
> alert--which saves space and resources.  Can this be replicated with snort's unified2 output mode (which I currently 
> use)? If so, how can I query the binary file for the specific intrusion event?
>
> Thanks.
>
>
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