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Split out more SMTP analysis functionality.

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This commit is contained in:
Seth Hall 2011-08-11 08:26:20 -04:00
parent d201215359
commit b45c175147
2 changed files with 61 additions and 50 deletions
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49
scripts/base/protocols/smtp/main.bro
View file

@ -4,13 +4,6 @@ module SMTP;
export {
redef enum Log::ID += { SMTP };
redef enum Notice::Type += {
## Indicates that the server sent a reply mentioning an SMTP block list.
BL_Error_Message,
## Indicates the client's address is seen in the block list error message.
BL_Blocked_Host,
};
type Info: record {
ts: time &log;
uid: string &log;
@ -60,25 +53,6 @@ export {
## NO_HOSTS - never capture the path.
const mail_path_capture = ALL_HOSTS &redef;
# This matches content in SMTP error messages that indicate some
# block list doesn't like the connection/mail.
const bl_error_messages =
/spamhaus\.org\//
| /sophos\.com\/security\//
| /spamcop\.net\/bl/
| /cbl\.abuseat\.org\//
| /sorbs\.net\//
| /bsn\.borderware\.com\//
| /mail-abuse\.com\//
| /b\.barracudacentral\.com\//
| /psbl\.surriel\.com\//
| /antispam\.imp\.ch\//
| /dyndns\.com\/.*spam/
| /rbl\.knology\.net\//
| /intercept\.datapacket\.net\//
| /uceprotect\.net\//
| /hostkarma\.junkemailfilter\.com\// &redef;
global log_smtp: event(rec: Info);
## Configure the default ports for SMTP analysis.
@ -181,27 +155,6 @@ event smtp_reply(c: connection, is_orig: bool, code: count, cmd: string,
# This continually overwrites, but we want the last reply,
# so this actually works fine.
c$smtp$last_reply = fmt("%d %s", code, msg);
if ( code != 421 && code >= 400 )
{
# Raise a notice when an SMTP error about a block list is discovered.
if ( bl_error_messages in msg )
{
local note = BL_Error_Message;
local message = fmt("%s received an error message mentioning an SMTP block list", c$id$orig_h);
# Determine if the originator's IP address is in the message.
local ips = find_ip_addresses(msg);
local text_ip = "";
if ( |ips| > 0 && to_addr(ips[0]) == c$id$orig_h )
{
note = BL_Blocked_Host;
message = fmt("%s is on an SMTP block list", c$id$orig_h);
}
NOTICE([$note=note, $conn=c, $msg=message, $sub=msg]);
}
}
}
event smtp_reply(c: connection, is_orig: bool, code: count, cmd: string,
@ -256,7 +209,7 @@ event mime_one_header(c: connection, h: mime_header_rec) &priority=5
else if ( h$name == "X-ORIGINATING-IP" )
{
local addresses = find_ip_addresses(h$name);
local addresses = find_ip_addresses(h$value);
if ( 1 in addresses )
c$smtp$x_originating_ip = to_addr(addresses[1]);
}

58
scripts/policy/protocols/smtp/blocklists.bro Normal file
View file

@ -0,0 +1,58 @@
@load base/protocols/smtp
module SMTP;
export {
redef enum Notice::Type += {
## Indicates that the server sent a reply mentioning an SMTP block list.
Blocklist_Error_Message,
## Indicates the client's address is seen in the block list error message.
Blocklist_Blocked_Host,
};
# This matches content in SMTP error messages that indicate some
# block list doesn't like the connection/mail.
const blocklist_error_messages =
/spamhaus\.org\//
| /sophos\.com\/security\//
| /spamcop\.net\/bl/
| /cbl\.abuseat\.org\//
| /sorbs\.net\//
| /bsn\.borderware\.com\//
| /mail-abuse\.com\//
| /b\.barracudacentral\.com\//
| /psbl\.surriel\.com\//
| /antispam\.imp\.ch\//
| /dyndns\.com\/.*spam/
| /rbl\.knology\.net\//
| /intercept\.datapacket\.net\//
| /uceprotect\.net\//
| /hostkarma\.junkemailfilter\.com\// &redef;
}
event smtp_reply(c: connection, is_orig: bool, code: count, cmd: string,
msg: string, cont_resp: bool) &priority=3
{
if ( code >= 400 && code != 421 )
{
# Raise a notice when an SMTP error about a block list is discovered.
if ( blocklist_error_messages in msg )
{
local note = Blocklist_Error_Message;
local message = fmt("%s received an error message mentioning an SMTP block list", c$id$orig_h);
# Determine if the originator's IP address is in the message.
local ips = find_ip_addresses(msg);
local text_ip = "";
if ( |ips| > 0 && to_addr(ips[0]) == c$id$orig_h )
{
note = Blocklist_Blocked_Host;
message = fmt("%s is on an SMTP block list", c$id$orig_h);
}
NOTICE([$note=note, $conn=c, $msg=message, $sub=msg]);
}
}
}