Aug 27 04:55:26 mail.srvfarm.net postfix/smtps/smtpd[1335344]: warning: unknown[186.216.68.156]: SASL PLAIN authentication failed: 
Aug 27 04:55:27 mail.srvfarm.net postfix/smtps/smtpd[1335344]: lost connection after AUTH from unknown[186.216.68.156]
Aug 27 04:58:56 mail.srvfarm.net postfix/smtpd[1336010]: warning: unknown[186.216.68.156]: SASL PLAIN authentication failed: 
Aug 27 04:58:57 mail.srvfarm.net postfix/smtpd[1336010]: lost connection after AUTH from unknown[186.216.68.156]
Aug 27 05:04:12 mail.srvfarm.net postfix/smtpd[1341948]: warning: unknown[186.216.68.156]: SASL PLAIN authentication failed:

Attempted Brute Force (dovecot)

Aug 30 07:47:56 mail.srvfarm.net postfix/smtps/smtpd[3605554]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed: 
Aug 30 07:47:57 mail.srvfarm.net postfix/smtps/smtpd[3605554]: lost connection after AUTH from unknown[186.216.68.183]
Aug 30 07:48:43 mail.srvfarm.net postfix/smtpd[3603899]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed: 
Aug 30 07:48:44 mail.srvfarm.net postfix/smtpd[3603899]: lost connection after AUTH from unknown[186.216.68.183]
Aug 30 07:51:40 mail.srvfarm.net postfix/smtps/smtpd[3603756]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed:

Aug 30 07:47:56 mail.srvfarm.net postfix/smtps/smtpd[3605554]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed: 
Aug 30 07:47:57 mail.srvfarm.net postfix/smtps/smtpd[3605554]: lost connection after AUTH from unknown[186.216.68.183]
Aug 30 07:48:43 mail.srvfarm.net postfix/smtpd[3603899]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed: 
Aug 30 07:48:44 mail.srvfarm.net postfix/smtpd[3603899]: lost connection after AUTH from unknown[186.216.68.183]
Aug 30 07:51:40 mail.srvfarm.net postfix/smtps/smtpd[3603756]: warning: unknown[186.216.68.183]: SASL PLAIN authentication failed:

failed_logins

Aug 27 04:33:42 mail.srvfarm.net postfix/smtps/smtpd[1331222]: warning: unknown[186.216.68.222]: SASL PLAIN authentication failed: 
Aug 27 04:33:43 mail.srvfarm.net postfix/smtps/smtpd[1331222]: lost connection after AUTH from unknown[186.216.68.222]
Aug 27 04:37:40 mail.srvfarm.net postfix/smtps/smtpd[1314660]: warning: unknown[186.216.68.222]: SASL PLAIN authentication failed: 
Aug 27 04:37:40 mail.srvfarm.net postfix/smtps/smtpd[1314660]: lost connection after AUTH from unknown[186.216.68.222]
Aug 27 04:40:50 mail.srvfarm.net postfix/smtps/smtpd[1335343]: warning: unknown[186.216.68.222]: SASL PLAIN authentication failed:

Aug 17 05:30:57 mail.srvfarm.net postfix/smtps/smtpd[2599208]: warning: unknown[186.216.68.162]: SASL PLAIN authentication failed: 
Aug 17 05:30:57 mail.srvfarm.net postfix/smtps/smtpd[2599208]: lost connection after AUTH from unknown[186.216.68.162]
Aug 17 05:39:39 mail.srvfarm.net postfix/smtps/smtpd[2601414]: warning: unknown[186.216.68.162]: SASL PLAIN authentication failed: 
Aug 17 05:39:39 mail.srvfarm.net postfix/smtps/smtpd[2601414]: lost connection after AUTH from unknown[186.216.68.162]
Aug 17 05:39:54 mail.srvfarm.net postfix/smtps/smtpd[2602315]: warning: unknown[186.216.68.162]: SASL PLAIN authentication failed:

Aug 15 02:33:35 mail.srvfarm.net postfix/smtpd[966773]: warning: unknown[186.216.68.192]: SASL PLAIN authentication failed: 
Aug 15 02:33:36 mail.srvfarm.net postfix/smtpd[966773]: lost connection after AUTH from unknown[186.216.68.192]
Aug 15 02:34:18 mail.srvfarm.net postfix/smtps/smtpd[963401]: warning: unknown[186.216.68.192]: SASL PLAIN authentication failed: 
Aug 15 02:34:19 mail.srvfarm.net postfix/smtps/smtpd[963401]: lost connection after AUTH from unknown[186.216.68.192]
Aug 15 02:37:51 mail.srvfarm.net postfix/smtps/smtpd[969052]: warning: unknown[186.216.68.192]: SASL PLAIN authentication failed:

Jul 25 04:59:28 mail.srvfarm.net postfix/smtps/smtpd[352431]: warning: unknown[186.216.68.130]: SASL PLAIN authentication failed: 
Jul 25 04:59:29 mail.srvfarm.net postfix/smtps/smtpd[352431]: lost connection after AUTH from unknown[186.216.68.130]
Jul 25 05:08:26 mail.srvfarm.net postfix/smtps/smtpd[365292]: warning: unknown[186.216.68.130]: SASL PLAIN authentication failed: 
Jul 25 05:08:26 mail.srvfarm.net postfix/smtps/smtpd[365292]: lost connection after AUTH from unknown[186.216.68.130]
Jul 25 05:09:21 mail.srvfarm.net postfix/smtps/smtpd[365718]: lost connection after CONNECT from unknown[186.216.68.130]

Jul 24 09:46:07 mail.srvfarm.net postfix/smtps/smtpd[2158496]: warning: unknown[186.216.68.149]: SASL PLAIN authentication failed: 
Jul 24 09:46:07 mail.srvfarm.net postfix/smtps/smtpd[2158496]: lost connection after AUTH from unknown[186.216.68.149]
Jul 24 09:50:50 mail.srvfarm.net postfix/smtps/smtpd[2161003]: warning: unknown[186.216.68.149]: SASL PLAIN authentication failed: 
Jul 24 09:50:50 mail.srvfarm.net postfix/smtps/smtpd[2161003]: lost connection after AUTH from unknown[186.216.68.149]
Jul 24 09:51:17 mail.srvfarm.net postfix/smtps/smtpd[2164483]: warning: unknown[186.216.68.149]: SASL PLAIN authentication failed:

SASL PLAIN auth failed: ruser=...

2020-07-07 16:26:48 plain_virtual_exim authenticator failed for ([186.216.68.197]) [186.216.68.197]: 535 Incorrect authentication data


........
-----------------------------------------------
https://www.blocklist.de/en/view.html?ip=186.216.68.197

(smtpauth) Failed SMTP AUTH login from 186.216.68.203 (BR/Brazil/186-216-68-203.uni-wr.mastercabo.com.br): 1 in the last 3600 secs; Ports: *; Direction: inout; Trigger: LF_TRIGGER; Logs: 2020-06-29 15:38:03 plain authenticator failed for ([186.216.68.203]) [186.216.68.203]: 535 Incorrect authentication data (set_id=info@kooshanetesal.com)

Brute force attack to crack SMTP password (port 25 / 587)

Jun 16 05:07:22 mail.srvfarm.net postfix/smtps/smtpd[917496]: warning: unknown[186.216.68.85]: SASL PLAIN authentication failed: 
Jun 16 05:07:23 mail.srvfarm.net postfix/smtps/smtpd[917496]: lost connection after AUTH from unknown[186.216.68.85]
Jun 16 05:08:17 mail.srvfarm.net postfix/smtps/smtpd[915906]: lost connection after CONNECT from unknown[186.216.68.85]
Jun 16 05:13:52 mail.srvfarm.net postfix/smtps/smtpd[935106]: warning: unknown[186.216.68.85]: SASL PLAIN authentication failed: 
Jun 16 05:13:53 mail.srvfarm.net postfix/smtps/smtpd[935106]: lost connection after AUTH from unknown[186.216.68.85]

Jun 16 05:35:15 mail.srvfarm.net postfix/smtps/smtpd[956591]: lost connection after CONNECT from unknown[186.216.68.168]
Jun 16 05:37:52 mail.srvfarm.net postfix/smtpd[953487]: warning: unknown[186.216.68.168]: SASL PLAIN authentication failed: 
Jun 16 05:37:53 mail.srvfarm.net postfix/smtpd[953487]: lost connection after AUTH from unknown[186.216.68.168]
Jun 16 05:39:49 mail.srvfarm.net postfix/smtpd[953480]: lost connection after CONNECT from unknown[186.216.68.168]
Jun 16 05:40:32 mail.srvfarm.net postfix/smtps/smtpd[937454]: warning: unknown[186.216.68.168]: SASL PLAIN authentication failed:

May 21 03:59:49 ssh2 sshd[97748]: User root from 192.42.116.16 not allowed because not listed in AllowUsers
May 21 03:59:49 ssh2 sshd[97748]: Failed password for invalid user root from 192.42.116.16 port 48768 ssh2
May 21 03:59:49 ssh2 sshd[97748]: Failed password for invalid user root from 192.42.116.16 port 48768 ssh2
...

2020-05-20T17:03:44.505680-07:00 suse-nuc sshd[11251]: Invalid user wyn from 14.29.214.233 port 36656
...

SSH Bruteforce Attempt (failed auth)

May 21 02:15:06 ArkNodeAT sshd\[16476\]: Invalid user fvj from 186.138.196.50
May 21 02:15:06 ArkNodeAT sshd\[16476\]: pam_unix\(sshd:auth\): authentication failure\; logname= uid=0 euid=0 tty=ssh ruser= rhost=186.138.196.50
May 21 02:15:08 ArkNodeAT sshd\[16476\]: Failed password for invalid user fvj from 186.138.196.50 port 45040 ssh2

May 21 05:59:27 pve1 sshd[10458]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=200.233.163.65 
May 21 05:59:30 pve1 sshd[10458]: Failed password for invalid user wzx from 200.233.163.65 port 41076 ssh2
...

Automatic report - Port Scan Attack

[2020-05-20 23:55:48] NOTICE[1157] chan_sip.c: Registration from '' failed for '5.39.71.23:55620' - Wrong password
[2020-05-20 23:55:48] SECURITY[1173] res_security_log.c: SecurityEvent="InvalidPassword",EventTV="2020-05-20T23:55:48.080-0400",Severity="Error",Service="SIP",EventVersion="2",AccountID="3422",SessionID="0x7f5f10385c48",LocalAddress="IPV4/UDP/192.168.244.6/5060",RemoteAddress="IPV4/UDP/5.39.71.23/55620",Challenge="3b889916",ReceivedChallenge="3b889916",ReceivedHash="30e7d6af439fe86265095df00f68408e"
[2020-05-20 23:59:32] NOTICE[1157] chan_sip.c: Registration from '' failed for '5.39.71.23:62926' - Wrong password
[2020-05-20 23:59:32] SECURITY[1173] res_security_log.c: SecurityEvent="InvalidPassword",EventTV="2020-05-20T23:59:32.614-0400",Severity="Error",Service="SIP",EventVersion="2",AccountID="2567",SessionID="0x7f5f1051dd08",LocalAddress="IPV4/UDP/192.168.244.6/5060",RemoteAddress="IPV4/UDP/5.39.71.23/62926",Chal
...

May 21 01:59:11 legacy sshd[10226]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=181.48.46.195
May 21 01:59:13 legacy sshd[10226]: Failed password for invalid user pem from 181.48.46.195 port 50797 ssh2
May 21 02:04:09 legacy sshd[10417]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=181.48.46.195
...

May 21 01:44:34 pl3server sshd[27297]: Invalid user pi from 178.142.126.34 port 57838
May 21 01:44:34 pl3server sshd[27298]: Invalid user pi from 178.142.126.34 port 57840
May 21 01:44:34 pl3server sshd[27297]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=178.142.126.34
May 21 01:44:34 pl3server sshd[27298]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=178.142.126.34
May 21 01:44:36 pl3server sshd[27297]: Failed password for invalid user pi from 178.142.126.34 port 57838 ssh2
May 21 01:44:37 pl3server sshd[27298]: Failed password for invalid user pi from 178.142.126.34 port 57840 ssh2
May 21 01:44:37 pl3server sshd[27297]: Connection closed by 178.142.126.34 port 57838 [preauth]
May 21 01:44:37 pl3server sshd[27298]: Connection closed by 178.142.126.34 port 57840 [preauth]


........
-----------------------------------------------
https://www.blocklist.de/en/view.html?ip=178.142.126.34

From return-aluguel=marcoslimaimoveis.com.br@vendassaudeonline.we.bs Wed May 20 21:03:37 2020
Received: from ven01859-mx-2.vendassaudeonline.we.bs ([51.91.163.159]:45904)

May 21 01:54:08 buvik sshd[26409]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=106.13.61.165
May 21 01:54:10 buvik sshd[26409]: Failed password for invalid user oyr from 106.13.61.165 port 49828 ssh2
May 21 02:04:08 buvik sshd[28148]: Invalid user bhu from 106.13.61.165
...

May 21 01:59:54 home sshd[4958]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=111.230.210.229
May 21 01:59:57 home sshd[4958]: Failed password for invalid user elc from 111.230.210.229 port 59392 ssh2
May 21 02:04:05 home sshd[5673]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=111.230.210.229
...

Found by fail2ban

May 21 02:03:00 minden010 sshd[3204]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=192.99.12.24
May 21 02:03:02 minden010 sshd[3204]: Failed password for invalid user xvv from 192.99.12.24 port 53710 ssh2
May 21 02:03:39 minden010 sshd[3294]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=192.99.12.24
...

May 21 02:01:39 minden010 sshd[3016]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=40.115.247.138
May 21 02:01:40 minden010 sshd[3016]: Failed password for invalid user add from 40.115.247.138 port 34172 ssh2
May 21 02:03:34 minden010 sshd[3260]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=40.115.247.138
...