zeek/policy/protocols/smtp/detect-suspicious-orig.bro
Seth Hall b307cbbe64 Large reorganization.
- Scripts now use the full path for @load to remove the subpaths
  from the shipped BROPATH.
- Some script sets have been reorganized to make optional loads
  more obvious.
2011-07-08 00:04:01 -04:00

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module SMTP;
@load frameworks/notice
@load protocols/smtp/base
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$country_code in suspicious_origination_countries ||
ip in suspicious_origination_networks )
{
NOTICE([$note=Suspicious_Origination,
$msg=fmt("An email originated from %s (%s).", loc$country_code, ip),
$id=rec$id]);
}
}
if ( rec?$path )
{
ip = rec$path[|rec$path|-1];
loc = lookup_location(ip);
if ( loc$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, ip),
$id=rec$id]);
}
}
}