파일에 로그를 기록하기 위해 /etc/rc.local에 다음 줄을 사용하여 /var/log/auth.log 설정에 busybox-syslogd 로깅을 사용하여 Debian 9에서 fail2ban(0.9.6-2)을 실행하고 있습니다.
/sbin/syslogd -O /var/log/auth.log || exit 1
SSHD 감옥이 활성화되었지만 실패한 로그인 시도가 표시되지 않습니다.
sshd 필터를 사용하여 auth.log 파일에서 실패2ban-regex를 실행하면 실패가 발생하지 않습니다.
sshd_config가 AUTHPRIV 및 VERBOSE로 설정됨
다음은 auth.log 로그 샘플입니다.
Jan 14 17:12:41 Fire-Video authpriv.info sshd[2556]: Failed none for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd[2556]: Failed password for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd[2556]: Failed password for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd[2556]: Connection closed by 192.168.60.5 port 56068 [preauth]
Jan 14 17:12:49 Fire-Video authpriv.info sshd[2558]: Connection from 192.168.60.5 port 56074 on 192.168.40.19 port 22
Jan 14 17:12:53 Fire-Video authpriv.debug sshd[2558]: pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:12:53 Fire-Video authpriv.notice sshd[2558]: pam_usermapper(sshd:auth): aliasing to 'root'
Jan 14 17:12:53 Fire-Video authpriv.notice sshd[2558]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=192.168.60.5 user=root
Jan 14 17:12:55 Fire-Video authpriv.info sshd[2558]: Failed password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:15 Fire-Video authpriv.debug sshd[2558]: pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:13:16 Fire-Video authpriv.info sshd[2558]: Failed password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:21 Fire-Video authpriv.debug sshd[2558]: pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:13:21 Fire-Video authpriv.info sshd[2558]: Accepted password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:21 Fire-Video authpriv.info sshd[2558]: pam_unix(sshd:session): session opened for user root by (uid=0)
이것은 filter.d의 내 sshd.conf입니다.
# PasswordAuthentication in sshd_config.
#
#
# "Connection from <HOST> port \d+" requires LogLevel VERBOSE in sshd_config
#
[INCLUDES]
# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf
[Definition]
_daemon = sshd
failregex = ^%(__prefix_line)s(?:error: PAM: )?[aA]uthentication (?:failure|error|failed) for .* from <HOST>( via \S+)?\s*$
^%(__prefix_line)s(?:error: PAM: )?User not known to the underlying authentication module for .* from <HOST>\s*$
^%(__prefix_line)sFailed \S+ for (?P<cond_inv>invalid user )?(?P<user>(?P<cond_user>\S+)|(?(cond_inv)(?:(?! from ).)*?|[^:]+)) from <HOST>(?: port \d+)?(?: ssh\d*)?(?(cond_user):|(?:(?:(?! from ).)*)$)
^%(__prefix_line)sROOT LOGIN REFUSED.* FROM <HOST>\s*$
^%(__prefix_line)s[iI](?:llegal|nvalid) user .*? from <HOST>(?: port \d+)?\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not listed in AllowUsers\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because listed in DenyUsers\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not in any group\s*$
^%(__prefix_line)srefused connect from \S+ \(<HOST>\)\s*$
^%(__prefix_line)s(?:error: )?Received disconnect from <HOST>: 3: .*: Auth fail(?: \[preauth\])?$
^%(__prefix_line)sUser .+ from <HOST> not allowed because a group is listed in DenyGroups\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because none of user's groups are listed in AllowGroups\s*$
^(?P<__prefix>%(__prefix_line)s)User .+ not allowed because account is locked<SKIPLINES>(?P=__prefix)(?:error: )?Received disconnect from <HOST>: 11: .+ \[preauth\]$
^(?P<__prefix>%(__prefix_line)s)Disconnecting: Too many authentication failures for .+? \[preauth\]<SKIPLINES>(?P=__prefix)(?:error: )?Connection closed by <HOST> \[preauth\]$
^(?P<__prefix>%(__prefix_line)s)Connection from <HOST> port \d+(?: on \S+ port \d+)?<SKIPLINES>(?P=__prefix)Disconnecting: Too many authentication failures for .+? \[preauth\]$
^%(__prefix_line)s(error: )?maximum authentication attempts exceeded for .* from <HOST>(?: port \d*)?(?: ssh\d*)? \[preauth\]$
^%(__prefix_line)spam_unix\(sshd:auth\):\s+authentication failure;\s*logname=\S*\s*uid=\d*\s*euid=\d*\s*tty=\S*\s*ruser=\S*\s*rhost=<HOST>\s.*$
ignoreregex =
[Init]
# "maxlines" is number of log lines to buffer for multi-line regex searches
maxlines = 10
journalmatch = _SYSTEMD_UNIT=sshd.service + _COMM=sshd
# DEV Notes:
#
# "Failed \S+ for .*? from <HOST>..." failregex uses non-greedy catch-all because
# it is coming before use of <HOST> which is not hard-anchored at the end as well,
# and later catch-all's could contain user-provided input, which need to be greedily
# matched away first.
#
# Author: Cyril Jaquier, Yaroslav Halchenko, Petr Voralek, Daniel Black
답변1
이들 모두의 문제는 __prefix_linebusybox syslogd의 이상한 로그 형식과 일치하지 않는다는 것입니다. 따라서 Fail2ban은 의미가 없습니다어느busybox에 의해 생성된 로그 항목입니다.
-Sbusybox syslogd가 다음과 같은 축약된 로그 형식을 사용하도록 하는 옵션을 사용해 볼 수 있습니다 .~해야 한다일치 __prefix_line하지만 일반 로그로는 덜 유용합니다.
/sbin/syslogd -S -O /var/log/auth.log || exit 1