zeek/scripts/policy/protocols/smtp/detect-suspicious-orig.bro
Jon Siwek 13a09aa488 Fixes for GeoIP support (addresses #538).
- Missing GeoIP databases now generate warnings/errors that go through
  the reporter framework instead of hitting GeoIP's internal use of
  stderr

- lookup_location now just queries for country code if the city database
  was not loaded, which gets rid of invalid database type errors.

- lookup_location now leaves missing fields uninitialized in the
  returned geo_location record value.  Updated existing scripts to
  check for initialized fields in geo_location records before use.

- Fixed support for GeoIP's IPv6 API and databases
2011-08-30 17:02:07 -05:00

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@load base/frameworks/notice/main
@load base/protocols/smtp/main
module SMTP;
export {
redef enum Notice::Type += {
Suspicious_Origination
};
## Places where it's suspicious for mail to originate from represented as
## all-capital, two character country codes (e.x. US). It requires
## libGeoIP support built in.
const suspicious_origination_countries: set[string] = {} &redef;
const suspicious_origination_networks: set[subnet] = {} &redef;
}
event log_smtp(rec: Info)
{
local ip: addr;
local loc: geo_location;
if ( rec?$x_originating_ip )
{
ip = rec$x_originating_ip;
loc = lookup_location(ip);
if ( (loc?$country_code &&
loc$country_code in suspicious_origination_countries) ||
ip in suspicious_origination_networks )
{
NOTICE([$note=Suspicious_Origination,
$msg=fmt("An email originated from %s (%s).",
loc?$country_code ? loc$country_code : "", ip),
$id=rec$id]);
}
}
if ( rec?$path )
{
ip = rec$path[|rec$path|-1];
loc = lookup_location(ip);
if ( (loc?$country_code &&
loc$country_code in suspicious_origination_countries) ||
ip in suspicious_origination_networks )
{
NOTICE([$note=Suspicious_Origination,
$msg=fmt("Based up Received headers, email originated from %s (%s).", loc?$country_code ? loc$country_code : "", ip),
$id=rec$id]);
}
}
}