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https://bro-tracker.atlassian.net/browse/BIT-1062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14000#comment-14000
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Jon Siwek commented on BIT-1062:
--------------------------------
{quote}
I was doing some testing with fragmented attacks trying to bypass IDS sensors
and noticed that BRO does not identify/populate the SRC & DST IP's in the weird
log
{quote}
They're probably missing since the weird log field is a conn_id (hosts and
ports), but flow_weirds (like what happens w/ IP fragments in this case) would
only have available the hosts, but not ports.
Seth, would it make sense to create a dummy conn_id w/ 0/unknown for the ports
so that hosts can at least be logged?
{quote}
... and other fields such as the URI in the http.log ...
{quote}
{quote}
Also,. I fragmented a GET /EVILSTUFF HTTP request,. and noticed:
1377056289.770819 - - - - - excessively_small_fragment - F bro
1377056289.787032 - - - - - fragment_inconsistency - F bro
1377056290.141267 iL6Ki3ncjV1 192.168.1.5 17384 192.168.1.16 80
unmatched_HTTP_reply - F bro
{quote}
I'm not sure fragments were generated right. They have Identification=1,
Fragment Offset=0, the More Fragments bit set, but with different data (i.e.
all fragments overlap). Unless there's suggestions, I'm not sure what more can
be done.
> Issues fragmented packets and BRO
> ---------------------------------
>
> Key: BIT-1062
> URL: https://bro-tracker.atlassian.net/browse/BIT-1062
> Project: Bro Issue Tracker
> Issue Type: Problem
> Components: Bro
> Affects Versions: 2.1
> Environment: Ubuntu/Debian
> Reporter: john blaze
> Attachments: fraggy_out_EVILSTUFF, more_frag.pcap
>
>
> I was doing some testing with fragmented attacks trying to bypass IDS sensors
> and noticed that BRO does not identify/populate the SRC & DST IP's in the
> weird log and other fields such as the URI in the http.log when doing stuff
> like:
> >>> f=fragment(IP(dst="80.69.77.211")/ICMP()/("X"*50), fragsize=10)
> >>> for frag in f:
> ... send(frag)
> 1377062338.222065 - - - - -
> excessively_small_fragment - F bro
> Also,. I fragmented a GET /EVILSTUFF HTTP request,. and noticed:
> 1377056289.770819 - - - - -
> excessively_small_fragment - F bro
> 1377056289.787032 - - - - -
> fragment_inconsistency - F bro
> 1377056290.141267 iL6Ki3ncjV1 192.168.1.5 17384 192.168.1.16
> 80 unmatched_HTTP_reply - F bro
> PCAPS are attached.
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