[Bro] File extraction exclude local sites

[Marius Portaas Haugen]

Hi Mike,

I have planned to do something similar myself, and I'm planning on 
using the
local_orig variable and test for something like
if(f$info?$local_org) return;

but I haven't tried it out yet.
 From the documentation 
(http://www.bro.org/sphinx-git/scripts/base/frameworks/files/main.bro.html#type-Files::Info):

local_orig: bool &log &optional
If the source of this file is a network connection, this field 
indicates if the data originated from the local network or not as 
determined by the configured Site::local_nets.

Maybe this could work?

Best regards,
Marius P. Haugen




On 2014-02-01 23:53, Mike Kolkebeck wrote:
> Does anyone have a solution to exclude extracting files transmitted
> from internal hosts?
> 
> I modified the script below from the bro exchange exercise, but I
> continue to get executable files from internal hosts.  I am using
> broctl and networks.cfg is populated.  I haven't tried using the
> file_over_new_connection event yet, but I would prefer to use file_new
> event, if I can.  Any ideas on what I'm doing wrong?
> 
> Thanks!
> Mike
> 
> global ext_map: table[string] of string = {
>      ["application/x-dosexec"] = "exe",
>  } &default ="";
> 
> event file_new(f: fa_file)
>      {
>      if ( ! f?$mime_type || f$mime_type != "application/x-dosexec" )
>          return;
>          
>      if ( ! f?$info || ! f$info?$tx_hosts )
>          return;
>      
>      for ( txhost in f$info$tx_hosts )
>          {
>          if ( Site::is_local_addr(txhost) )
>              return;
>          }
>      
>      local ext = "";
> 
>     if ( f?$mime_type )
>          ext = ext_map[f$mime_type];
> 
>     local fname = fmt("%s-%s.%s", f$source, f$id, ext);
>      Files::add_analyzer(f, Files::ANALYZER_EXTRACT, 
> [$extract_filename=fname]);
>      }
> 
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