# Sagan courier.rules
# Copyright (c) 2009-2020. Quadrant Information Security <www.quadrantsec.com>
# All rights reserved.
#
# Please submit any custom rules or ideas to sagan-submit@quadrantsec.com or the sagan-sigs mailing list
#
#*************************************************************
#  Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
#  following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice, this list of conditions and the following
#    disclaimer.
#  * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
#    following disclaimer in the documentation and/or other materials provided with the distribution.
#  * Neither the name of the nor the names of its contributors may be used to endorse or promote products derived
#    from this software without specific prior written permission.
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#  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#*************************************************************

#alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] Connection established"; content: "Connection,"; classtype: not-suspicious; program: courierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5000258; sid:5000258; rev:1;)

# Sep 24 12:29:52 bundy imapd: LOGIN FAILED, user=champtest, ip=[::ffff:10.0.0.1]

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] Authentication failure"; content: "LOGIN FAILED,"; parse_src_ip: 1; default_proto: tcp; classtype: unsuccessful-user; program: imapd|imapd-sslcourierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5000259; sid:5000259; rev:4;)

# Sep 23 07:29:40 bundy imapd-ssl: DISCONNECTED, user=champ, ip=[::ffff:10.0.0.1], headers=0, body=0, rcvd=70, sent=576, time=4, starttls=1
# Sep 24 07:14:17 bundy imapd-ssl: LOGOUT, user=champ, ip=[::ffff:10.0.0.1], headers=0, body=0, rcvd=1011, sent=9534, time=5, starttls=1

#alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] Logout/disconnect"; meta_content: "%sagan%",LOGOUT,DISCONNECTED; default_proto: tcp; classtype: not-suspicious; parse_src_ip: 1; program: imapd|imapd-ssl|courierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5000260; sid:5000260; rev:5;)

# May 24 16:03:15 bundy imapd-ssl: LOGIN, user=champ, ip=[::ffff:10.0.0.1], port=[45018], protocol=IMAP

#alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] User login"; content: "LOGIN,"; parse_src_ip: 1; default_proto: tcp; classtype: successful-user; program: imapd|imapd-ssl|courierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5000261; sid:5000261; rev:3;)

# May 24 16:44:21 bundy imapd-ssl: TIMEOUT, user=champ, ip=[::ffff:10.0.0.1], headers=104, body=19823, rcvd=474, sent=22380, time=2466, starttls=1

#alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] Timeout"; content: "TIMEOUT"; parse_src_ip: 1; default_proto: tcp; classtype: successful-user; program: imapd|imapd-ssl|courierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5002393; sid:5002393; rev:2;)

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[COURIER] Authentication failure - Brute Force [5/5]"; content: "LOGIN FAILED,"; parse_src_ip: 1; xbits: set,brute_force,track ip_src, expire 21600; after: track by_src, count 5, seconds 300; threshold: type suppress, track by_src, count 1, seconds 300; default_proto: tcp; classtype: unsuccessful-user; program: imapd|imapd-sslcourierlogger; reference: url,wiki.quadrantsec.com/bin/view/Main/5002398; sid:5002398; rev:6;)