Created
March 27, 2019 19:51
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Fail2Ban filter for postfix authentication failures, SASL Strict
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| # Fail2Ban filter for postfix authentication failures | |
| # more strict version of SASL Filter | |
| # EXAMPLE: | |
| # Mar 27 20:16:40 cc postfix/smtpd[959]: warning: unknown[123.123.123.123]: SASL PLAIN authentication failed: | |
| # | |
| [INCLUDES] | |
| before = common.conf | |
| [Definition] | |
| _daemon = postfix/(submission/)?smtp(d|s) | |
| failregex = ^%(__prefix_line)swarning: [-._\w]+\[<HOST>\]: SASL ((?i)LOGIN|PLAIN|(?:CRAM|DIGEST)-MD5) authentication failed:?(\s?[A-Za-z0-9+/:]*={0,4})?\s*$ | |
| ignoreregex = authentication failed: Connection lost to authentication server$ | |
| [Init] | |
| journalmatch = _SYSTEMD_UNIT=postfix.service | |
| # Author: Yaroslav Halchenko | |
| # +Marco Goetze (Fix more accurate for postfix 3.1 ) |
postfix/(submission/)?smtp(d|s) does not catch these kind of logs:
Mar 9 07:48:30 vps2053415 postfix/smtps/smtpd[7271]: warning: unknown[212.70.149.72]: SASL LOGIN authentication failed: authentication failure
I simply changed it to _daemon = postfix(/smtp(d|s)){1,2} while dropping the optional submission port, but I bet there is a nicer and cleaner variant.
Should be fine with e.g. _daemon = (?:postfix/smtp(d|s){1,2}|postfix/submission/smtp(d|s){1,2})
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Before (original filter):
Lines: 126338 lines, 0 ignored, 1692 matched, 124646 missed [processed in 5.17 sec]After (new filter):
Lines: 126338 lines, 0 ignored, 8578 matched, 117760 missed [processed in 5.13 sec]