fail2ban/config/filter.d/assp.conf

# Fail2Ban filter for Anti-Spam SMTP Proxy Server (ASSP)
#    Filter works in theory for both ASSP V1 and V2. Recommended ASSP is V2.5.1 or later.
#    Support for ASSP V1 ended in 2014 so if you are still running ASSP V1 an immediate upgrade is recommended.
#
#    Homepage:    http://sourceforge.net/projects/assp/
#    ProjectSite: http://sourceforge.net/projects/assp/?source=directory
#
#

[Definition] 
# Note: First three failregex matches below are for ASSP V1 with the remaining being designed for V2. Deleting the V1 regex is recommended but I left it in for compatibilty reasons.

__assp_actions = (?:dropping|refusing)

failregex = ^(:? \[SSL-out\])? <HOST> max sender authentication errors \(\d{,3}\) exceeded -- %(__assp_actions)s connection - after reply: \d{3} \d{1}\.\d{1}.\d{1} Error: authentication failed: \w+;$
			^(?: \[SSL-out\])? <HOST> SSL negotiation with client failed: SSL accept attempt failed with unknown error.*:unknown protocol;$
			^ Blocking <HOST> - too much AUTH errors \(\d{,3}\);$
			^\s*(?:[\w\-]+\s+)*(?:\[\S+\]\s+)*<HOST> (?:\<\S+@\S+\.\S+\> )*(?:to: \S+@\S+\.\S+ )*relay attempt blocked for(?: \(parsing\))?: \S+$
			^\s*(?:[\w\-]+\s+)*(?:\[\S+\]\s+)*<HOST> \[SMTP Error\] 535 5\.7\.8 Error: authentication failed:\s+(?:\S+|Connection lost to authentication server|Invalid authentication mechanism|Invalid base64 data in continued response)?$

ignoreregex = 

# DEV Notes:
# V1 Examples matches:
#   Apr-27-13 02:33:09 Blocking 217.194.197.97 - too much AUTH errors (41);
#   Dec-29-12 17:10:31 [SSL-out] 200.247.87.82 SSL negotiation with client failed: SSL accept attempt failed with unknown errorerror:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol;
#   Dec-30-12 04:01:47 [SSL-out] 81.82.232.66 max sender authentication errors (5) exceeded 
#
# V2 Examples matches:
#   Jul-29-16 16:49:52 m1-25391-06124 [Worker_1] [TLS-out] [RelayAttempt] 0.0.0.0 <user@example.com> to: user@example.org relay attempt blocked for: someone@example.org
#   Jul-30-16 16:59:42 [Worker_1] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: UGFzc3dvcmQ6
#   Jul-30-16 00:15:36 m1-52131-09651 [Worker_1] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: UGFzc3dvcmQ6
#   Jul-31-16 06:45:59 [Worker_1] [TLS-in] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed:
#   Jan-05-16 08:38:49 m1-01129-09140 [Worker_1] [TLS-in] [TLS-out] [RelayAttempt] 0.0.0.0 <user@example.com> relay attempt blocked for (parsing): <user2@example>
#   Jun-12-16 16:43:37 m1-64217-12013 [Worker_1] [TLS-in] [TLS-out] [RelayAttempt] 0.0.0.0 <user@example.com> to: user2@example.com relay attempt blocked for (parsing): <a.notheruser69@example.c>
#   Jan-22-16 22:25:51 [Worker_1] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: Invalid authentication mechanism
#   Mar-19-16 13:42:20 [Worker_1] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: Invalid base64 data in continued response
#   Jul-18-16 16:54:21 [Worker_2] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: Connection lost to authentication server
#   Jul-18-16 17:14:23 m1-76453-02949 [Worker_1] [TLS-out] 0.0.0.0 [SMTP Error] 535 5.7.8 Error: authentication failed: Connection lost to authentication server

#
# Author: Enrico Labedzki (enrico.labedzki@deiwos.de)
# V2 Filters: Robert Hardy (rhardy@webcon.ca)