filter.d/dovecot.conf: fixed "Authentication failure" regex, matches "Password mismatch" in title case (gh-2880)

config/filter.d/dovecot.conf

@@ -14,8 +14,8 @@ prefregex = ^%(__prefix_line)s(?:%(_auth_worker)s(?:\([^\)]+\))?: )?(?:%(__pam_a
 
 failregex = ^authentication failure; logname=<F-ALT_USER1>\S*</F-ALT_USER1> uid=\S* euid=\S* tty=dovecot ruser=<F-USER>\S*</F-USER> rhost=<HOST>(?:\s+user=<F-ALT_USER>\S*</F-ALT_USER>)?\s*$
             ^(?:Aborted login|Disconnected|Remote closed connection|Client has quit the connection)(?::(?: [^ \(]+)+)? \((?:auth failed, \d+ attempts(?: in \d+ secs)?|tried to use (?:disabled|disallowed) \S+ auth|proxy dest auth failed)\):(?: user=<<F-USER>[^>]*</F-USER>>,)?(?: method=\S+,)? rip=<HOST>(?:[^>]*(?:, session=<\S+>)?)\s*$
-            ^pam\(\S+,<HOST>(?:,\S*)?\): pam_authenticate\(\) failed: (?:User not known to the underlying authentication module: \d+ Time\(s\)|Authentication failure \(password mismatch\?\)|Permission denied)\s*$
+            ^pam\(\S+,<HOST>(?:,\S*)?\): pam_authenticate\(\) failed: (?:User not known to the underlying authentication module: \d+ Time\(s\)|Authentication failure \([Pp]assword mismatch\?\)|Permission denied)\s*$
-            ^[a-z\-]{3,15}\(\S*,<HOST>(?:,\S*)?\): (?:unknown user|invalid credentials|Password mismatch)
+            ^[a-z\-]{3,15}\(\S*,<HOST>(?:,\S*)?\): (?:[Uu]nknown user|[Ii]nvalid credentials|[Pp]assword mismatch)
             <mdre-<mode>>
 
 mdre-aggressive = ^(?:Aborted login|Disconnected|Remote closed connection|Client has quit the connection)(?::(?: [^ \(]+)+)? \((?:no auth attempts|disconnected before auth was ready,|client didn't finish \S+ auth,)(?: (?:in|waited) \d+ secs)?\):(?: user=<[^>]*>,)?(?: method=\S+,)? rip=<HOST>(?:[^>]*(?:, session=<\S+>)?)\s*$

fail2ban/tests/files/logs/dovecot

@@ -34,6 +34,9 @@ Jul 02 13:49:32 hostname dovecot[442]: dovecot: auth(default): pam(account@MYSER
 # failJSON: { "time": "2005-01-29T05:32:50", "match": true , "host": "1.2.3.4" }
 Jan 29 05:32:50 mail dovecot: auth-worker(304): pam(username,1.2.3.4): pam_authenticate() failed: Authentication failure (password mismatch?)
 
+# failJSON: { "time": "2005-01-29T18:55:55", "match": true , "host": "192.0.2.4", "desc": "Password mismatch (title case, gh-2880)" }
+Jan 29 18:55:55 mail dovecot: auth-worker(12182): pam(user,192.0.2.4): pam_authenticate() failed: Authentication failure (Password mismatch?)
+
 # failJSON: { "time": "2005-01-29T05:13:40", "match": true , "host": "1.2.3.4" }
 Jan 29 05:13:40 mail dovecot: auth-worker(31326): pam(username,1.2.3.4): unknown user