Fail2Ban 没有添加 iptables 规则

Question

Fail2Ban 没有添加 iptables 规则来阻止攻击者。我正在运行 CentOS 6.5（32 位）

这是我所做的：

• fail2ban 是使用 EPEL 存储库通过 yum 安装的。
• 我复制jail.conf到jail.local.

• 我将 jail.local 中的禁止时间更改为 3600

  bantime  = 3600
  

对于 iptables，我定义了这些关于 SSH 的规则

Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination         
1    ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
2    ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           state ESTABLISHED 
3    fail2ban-SSH  tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:22 
4    ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:22 

我jail.local的 SSH 配置：

[ssh-iptables]

enabled  = true
filter   = sshd
action   = iptables[name=SSH, port=ssh, protocol=tcp]
logpath  = /var/log/secure
maxretry = 5

最新日志条目：

2014-08-13 10:11:04,481 fail2ban.server : INFO   Changed logging target to /var/log/fail2ban.log for Fail2ban v0.8.11
2014-08-13 10:11:04,482 fail2ban.jail   : INFO   Creating new jail 'ssh-iptables'
2014-08-13 10:11:04,514 fail2ban.jail   : INFO   Jail 'ssh-iptables' uses pyinotify
2014-08-13 10:11:04,533 fail2ban.jail   : INFO   Initiated 'pyinotify' backend
2014-08-13 10:11:04,536 fail2ban.filter : INFO   Added logfile = /var/log/secure
2014-08-13 10:11:04,537 fail2ban.filter : INFO   Set maxRetry = 5
2014-08-13 10:11:04,540 fail2ban.filter : INFO   Set findtime = 600
2014-08-13 10:11:04,540 fail2ban.actions: INFO   Set banTime = 3600
2014-08-13 10:11:04,727 fail2ban.jail   : INFO   Jail 'ssh-iptables' started

然后我开始fail2ban，但过了一段时间（一个小时左右）我检查了一下/var/log/secure，我仍然受到蛮力攻击：

Aug 13 10:31:35 webhost sshd[15619]: Invalid user china from 128.199.147.79
Aug 13 10:31:35 webhost sshd[15620]: input_userauth_request: invalid user china
Aug 13 10:31:36 webhost sshd[15620]: Connection closed by 128.199.147.79
Aug 13 10:35:04 webhost sshd[15661]: Invalid user klaudia from 106.187.90.33
Aug 13 10:35:04 webhost sshd[15662]: input_userauth_request: invalid user klaudia
Aug 13 10:35:05 webhost sshd[15662]: Connection closed by 106.187.90.33
Aug 13 10:41:56 webhost sshd[15772]: Invalid user cassandra from 106.187.90.33
Aug 13 10:41:56 webhost sshd[15773]: input_userauth_request: invalid user cassandra
Aug 13 10:41:57 webhost sshd[15773]: Connection closed by 106.187.90.33
Aug 13 10:44:10 webhost sshd[15807]: Invalid user knight from 106.187.90.33
Aug 13 10:44:10 webhost sshd[15808]: input_userauth_request: invalid user knight
Aug 13 10:44:12 webhost sshd[15808]: Connection closed by 106.187.90.33

iptables 没有添加新规则...

Chain fail2ban-SSH (1 references)
target     prot opt source               destination         
RETURN     all  --  0.0.0.0/0            0.0.0.0/0 

如果我尝试使用以下方法调试问题fail2ban-regex：

fail2ban-regex  /var/log/secure /etc/fail2ban/filter.d/sshd.conf

Running tests

Use   failregex file : /etc/fail2ban/filter.d/sshd.conf
Use         log file : /var/log/secure

Results

Failregex: 1374 total
|-  #) [# of hits] regular expression
|   5) [1374] ^\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
|  [4615] MONTH Day Hour:Minute:Second
`-

Lines: 4615 lines, 0 ignored, 1374 matched, 3241 missed
Missed line(s):: too many to print.  Use --print-all-missed to print all 3241 lines
</code>

The missed lines are:

Lines: 4621 lines, 0 ignored, 1376 matched, 3245 missed
|- Missed line(s):
|  Aug 10 03:46:30 webhost sshd[12340]: input_userauth_request: invalid user simulator
|  Aug 10 03:46:30 webhost sshd[12340]: Connection closed by 106.187.90.33
|  Aug 10 03:55:01 webhost sshd[12430]: input_userauth_request: invalid user simulation
|  Aug 10 03:55:02 webhost sshd[12430]: Connection closed by 106.187.90.33
|  Aug 10 04:01:33 webhost sshd[12505]: Connection closed by 128.199.147.79
|  Aug 10 04:02:46 webhost sshd[12539]: reverse mapping checking getaddrinfo for new.jerl.im [128.199.254.179] failed - POSSIBLE BREAK-IN ATTEMPT!

我对fail2ban 的了解不够，无法知道我的sshd 过滤器有什么问题。我会认为默认配置就足够了？我该如何解决？

Answer 1

检查您是否启用了 IPTABLES Jail 和 SSH 过滤器。还要检查 f2b 日志 - f2b 是否试图禁止某人？