我正在嘗試讓 Fail2Ban 使用提供的 SSHD 配置。
當我跑步時：
fail2ban-regex /var/log/auth.log /etc/fail2ban/filter.d/sshd.conf
輸出是：
root@fw:/etc/fail2ban/filter.d# fail2ban-regex /var/log/auth.log /etc/fail2ban/filter.d/sshd.conf
Running tests
=============
Use failregex file : /etc/fail2ban/filter.d/sshd.conf
Use log file : /var/log/auth.log
Results
=======
Failregex: 5583 total
|- #) [# of hits] regular expression
| 3) [4339] ^\s*(<[^.]+\.[^.]+>)?\s*(?:\S+ )?(?:kernel: \[\d+\.\d+\] )?(?:@vserver_\S+ )?(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)?\s(?:\[ID \d+ \S+\])?\s*Failed \S+ for .*? from <HOST>(?: port \d*)?(?: ssh\d*)?(: (ruser .*|(\S+ ID \S+ \(serial \d+\) CA )?\S+ (?:[\da-f]{2}:){15}[\da-f]{2}(, client user ".*", client host ".*")?))?\s*$
| 5) [1244] ^\s*(<[^.]+\.[^.]+>)?\s*(?:\S+ )?(?:kernel: \[\d+\.\d+\] )?(?:@vserver_\S+ )?(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)?\s(?:\[ID \d+ \S+\])?\s*[iI](?:llegal|nvalid) user .* from <HOST>\s*$
`-
Ignoreregex: 0 total
Date template hits:
|- [# of hits] date format
| [19480] MONTH Day Hour:Minute:Second
`-
Lines: 19480 lines, 0 ignored, 5583 matched, 13897 missed
Missed line(s):: too many to print. Use --print-all-missed to print all 13897 lines
root@fw:/etc/fail2ban/filter.d#
我的 auth.log 看起來像這樣（範例）：
Oct 21 04:47:44 fw sshd[31558]: Disconnecting: Too many authentication failures for root [preauth]
Oct 21 04:47:44 fw sshd[31558]: PAM 5 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:44 fw sshd[31558]: PAM service(sshd) ignoring max retries; 6 > 3
Oct 21 04:47:46 fw sshd[31562]: Failed password for root from 218.2.0.125 port 12277 ssh2
Oct 21 04:47:46 fw sshd[31581]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:48 fw sshd[31560]: message repeated 5 times: [ Failed password for root from 218.2.0.125 port 9188 ssh2]
Oct 21 04:47:48 fw sshd[31560]: Disconnecting: Too many authentication failures for root [preauth]
Oct 21 04:47:48 fw sshd[31560]: PAM 5 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:48 fw sshd[31560]: PAM service(sshd) ignoring max retries; 6 > 3
Oct 21 04:47:48 fw sshd[31581]: Failed password for root from 218.2.0.125 port 13148 ssh2
Oct 21 04:47:52 fw sshd[31595]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:55 fw sshd[31595]: Failed password for root from 218.2.0.125 port 14409 ssh2
Oct 21 04:47:55 fw CRON[31494]: pam_unix(cron:session): session closed for user clamav
Oct 21 04:47:59 fw sshd[31562]: message repeated 5 times: [ Failed password for root from 218.2.0.125 port 12277 ssh2]
Oct 21 04:47:59 fw sshd[31562]: Disconnecting: Too many authentication failures for root [preauth]
Oct 21 04:47:59 fw sshd[31562]: PAM 5 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:59 fw sshd[31562]: PAM service(sshd) ignoring max retries; 6 > 3
Oct 21 04:47:59 fw sshd[31581]: message repeated 5 times: [ Failed password for root from 218.2.0.125 port 13148 ssh2]
Oct 21 04:47:59 fw sshd[31581]: Disconnecting: Too many authentication failures for root [preauth]
Oct 21 04:47:59 fw sshd[31581]: fatal: Write failed: Connection reset by peer [preauth]
Oct 21 04:47:59 fw sshd[31581]: PAM 5 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.2.0.125 user=root
Oct 21 04:47:59 fw sshd[31581]: PAM service(sshd) ignoring max retries; 6 > 3
Oct 21 04:48:00 fw sshd[31595]: message repeated 2 times: [ Failed password for root from 218.2.0.125 port 14409 ssh2]
我知道有些條目應該匹配，但我就是無法讓它匹配。
經過研究，我發現這可能與日期格式有關，但建議的更改common.conf沒有任何區別。
fail2ban-regex另外，我運行了一份日期格式為 auth.log 的手冊，它按預期返回。
答案1
看起來有匹配項，但還不夠。Debian 錯誤 #620364很可能是罪魁禍首。解決方法記錄在禁止失敗維基和堆疊溢位，就是關閉rsyslog中重複訊息減少：
sudo sed -i 's/RepeatedMsgReduction\ on/RepeatedMsgReduction\ off/' /etc/rsyslog.conf
sudo service rsyslog restart
sudo service fail2ban restart
答案2
Failed password for root
與 ssh 的 fail2ban 過濾器中的第三個條目正確匹配並已更正https://github.com/fail2ban/fail2ban/commit/750e0c1e3dbce856437c115142d57f18b6c1fac7。
message repeated 5 times
是重複訊息的結果，該訊息根據系統日誌變更進行修復（並且不需要fail2ban 重新啟動）。
PAM 5....
可以匹配，但是這將是第一個“密碼失敗..”日誌訊息的重複，並且沒有意義。
如果您遇到需要正規表示式的內容：
fail2ban-regex -D 'log line' /etc/fail2ban/filter.d/sshd.conf
並使用它應該匹配的正規表示式附近的 URL 並對其進行編輯，直到匹配為止。