Configurei o fail2ban para monitorar um determinado padrão de tráfego malicioso que estou recebendo e proibir endereços IP associados.
Tudo parece estar funcionando muito bem - o regex está correspondendo adequadamente ao padrão e o endereço IP do problema é adicionado ao iptables.
No entanto, quando eu verifico os logs do Apache, estou ainda recebendo hits do endereço IP que está sendo banido. É como se o iptables não estivesse rodando.
Então, deixe-me compartilhar alguns detalhes apenas para confirmar que tudo está configurado corretamente.
Primeiro, vou limpar e recarregar as regras do iptables:
$ sudo iptables -F
$ cat /etc/iptables.firewall.rules
*filter
# Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
# Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT
# Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT
# Allow SSH connections
#
# The -dport number should be the same port number you set in sshd_config
#
-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT
# Allow ping
-A INPUT -p icmp -j ACCEPT
# Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
# Drop all other inbound - default deny unless explicitly allowed policy
-A INPUT -j DROP
-A FORWARD -j DROP
COMMIT
$ sudo iptables-restore < /etc/iptables.firewall.rules
$ sudo iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 REJECT all -- * * 0.0.0.0/0 127.0.0.0/8 reject-with icmp-port-unreachable
14 1432 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
1 60 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:443
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/min burst 5 LOG flags 0 level 7 prefix "iptables denied: "
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
11 1638 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Agora, veja como é a configuração do fail2ban:
$ cat /etc/fail2ban/filter.d/apache-xmlrpc.conf
[Definition]
failregex = .*:80 <HOST> .*POST .*xmlrpc\.php.*
ignoreregex =
$ cat /etc/fail2ban/jail.local
[apache-xmlrpc]
enabled = true
port = http,https
filter = apache-xmlrpc
logpath = /var/log/apache2/other_vhosts_access.log
maxretry = 6
$ fail2ban-regex /var/log/apache2/other_vhosts_access.log /etc/fail2ban/filter.d/apache-xmlrpc.conf
Running tests
=============
Use regex file : /etc/fail2ban/filter.d/apache-xmlrpc.conf
Use log file : /var/log/apache2/other_vhosts_access.log
Results
=======
Failregex
|- Regular expressions:
| [1] .*:80 <HOST> .*POST .*xmlrpc\.php.*
|
'- Number of matches:
[1] 29 match(es)
Ignoreregex
|- Regular expressions:
|
'- Number of matches:
Summary
=======
Addresses found:
[1]
80.82.70.239 (Sat Jul 13 02:41:52 2013)
80.82.70.239 (Sat Jul 13 02:41:53 2013)
80.82.70.239 (Sat Jul 13 02:41:55 2013)
80.82.70.239 (Sat Jul 13 02:41:56 2013)
80.82.70.239 (Sat Jul 13 02:41:57 2013)
80.82.70.239 (Sat Jul 13 02:41:58 2013)
80.82.70.239 (Sat Jul 13 02:41:59 2013)
80.82.70.239 (Sat Jul 13 02:42:00 2013)
80.82.70.239 (Sat Jul 13 02:42:02 2013)
80.82.70.239 (Sat Jul 13 02:42:03 2013)
80.82.70.239 (Sat Jul 13 02:42:04 2013)
80.82.70.239 (Sat Jul 13 02:42:05 2013)
80.82.70.239 (Sat Jul 13 02:42:06 2013)
80.82.70.239 (Sat Jul 13 02:42:07 2013)
80.82.70.239 (Sat Jul 13 02:42:09 2013)
80.82.70.239 (Sat Jul 13 02:42:10 2013)
80.82.70.239 (Sat Jul 13 02:42:11 2013)
80.82.70.239 (Sat Jul 13 02:42:12 2013)
80.82.70.239 (Sat Jul 13 02:42:13 2013)
80.82.70.239 (Sat Jul 13 02:42:15 2013)
80.82.70.239 (Sat Jul 13 02:42:16 2013)
80.82.70.239 (Sat Jul 13 02:42:17 2013)
80.82.70.239 (Sat Jul 13 02:42:18 2013)
80.82.70.239 (Sat Jul 13 02:42:19 2013)
80.82.70.239 (Sat Jul 13 02:42:20 2013)
80.82.70.239 (Sat Jul 13 02:42:22 2013)
80.82.70.239 (Sat Jul 13 02:42:23 2013)
80.82.70.239 (Sat Jul 13 02:42:24 2013)
80.82.70.239 (Sat Jul 13 02:42:25 2013)
Date template hits:
0 hit(s): MONTH Day Hour:Minute:Second
0 hit(s): WEEKDAY MONTH Day Hour:Minute:Second Year
0 hit(s): WEEKDAY MONTH Day Hour:Minute:Second
0 hit(s): Year/Month/Day Hour:Minute:Second
0 hit(s): Day/Month/Year Hour:Minute:Second
0 hit(s): Day/Month/Year Hour:Minute:Second
70 hit(s): Day/MONTH/Year:Hour:Minute:Second
0 hit(s): Month/Day/Year:Hour:Minute:Second
0 hit(s): Year-Month-Day Hour:Minute:Second
0 hit(s): Year.Month.Day Hour:Minute:Second
0 hit(s): Day-MONTH-Year Hour:Minute:Second[.Millisecond]
0 hit(s): Day-Month-Year Hour:Minute:Second
0 hit(s): TAI64N
0 hit(s): Epoch
0 hit(s): ISO 8601
0 hit(s): Hour:Minute:Second
0 hit(s): <Month/Day/Year@Hour:Minute:Second>
Success, the total number of match is 29
However, look at the above section 'Running tests' which could contain important
information.
Como você pode ver, tenho um failregex configurado em um filtro e o filtro está ativado. Usando o fail2ban-regex, o filtro encontra uma correspondência no arquivo de log que estou monitorando. (Estou sendo atingido por um endereço IP problemático no momento, o que torna os testes bastante fáceis.)
Então, eu reinicio o fail2ban e observo as regras entrando em vigor:
$ sudo service fail2ban restart
* Restarting authentication failure monitor fail2ban [ OK ]
$ tail /var/log/fail2ban.log -n 50
2013-07-13 02:42:58,014 fail2ban.server : INFO Stopping all jails
2013-07-13 02:42:58,745 fail2ban.jail : INFO Jail 'apache-xmlrpc' stopped
2013-07-13 02:42:59,439 fail2ban.jail : INFO Jail 'ssh' stopped
2013-07-13 02:42:59,440 fail2ban.server : INFO Exiting Fail2ban
2013-07-13 02:43:08,055 fail2ban.server : INFO Changed logging target to /var/log/fail2ban.log for Fail2ban v0.8.6
2013-07-13 02:43:08,057 fail2ban.jail : INFO Creating new jail 'ssh'
2013-07-13 02:43:08,111 fail2ban.jail : INFO Jail 'ssh' uses Gamin
2013-07-13 02:43:08,397 fail2ban.filter : INFO Added logfile = /var/log/auth.log
2013-07-13 02:43:08,404 fail2ban.filter : INFO Set maxRetry = 6
2013-07-13 02:43:08,414 fail2ban.filter : INFO Set findtime = 600
2013-07-13 02:43:08,435 fail2ban.actions: INFO Set banTime = 600
2013-07-13 02:43:09,277 fail2ban.jail : INFO Creating new jail 'apache-xmlrpc'
2013-07-13 02:43:09,277 fail2ban.jail : INFO Jail 'apache-xmlrpc' uses Gamin
2013-07-13 02:43:09,283 fail2ban.filter : INFO Added logfile = /var/log/apache2/other_vhosts_access.log
2013-07-13 02:43:09,286 fail2ban.filter : INFO Set maxRetry = 6
2013-07-13 02:43:09,289 fail2ban.filter : INFO Set findtime = 600
2013-07-13 02:43:09,292 fail2ban.actions: INFO Set banTime = 600
2013-07-13 02:43:09,458 fail2ban.jail : INFO Jail 'ssh' started
2013-07-13 02:43:09,792 fail2ban.jail : INFO Jail 'apache-xmlrpc' started
2013-07-13 02:43:11,361 fail2ban.actions: WARNING [apache-xmlrpc] Ban 80.82.70.239
$ sudo iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
244 39277 fail2ban-apache-xmlrpc tcp -- * * 0.0.0.0/0 0.0.0.0/0 multiport dports 80,443
101 7716 fail2ban-ssh tcp -- * * 0.0.0.0/0 0.0.0.0/0 multiport dports 22
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 REJECT all -- * * 0.0.0.0/0 127.0.0.0/8 reject-with icmp-port-unreachable
3404 582K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
349 20900 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:443
12 720 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
2 80 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 5/min burst 5 LOG flags 0 level 7 prefix "iptables denied: "
2 80 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
3331 4393K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Chain fail2ban-apache-xmlrpc (1 references)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 80.82.70.239 0.0.0.0/0
244 39277 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0
Chain fail2ban-ssh (1 references)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 223.4.147.8 0.0.0.0/0
101 7716 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0
Como mostra o log do fail2ban, o conjunto de regras parece estar configurado corretamente. Você já pode ver que o endereço IP problemático está sendo capturado imediatamente e banido. A saída do iptables mostra que, de fato, está sendo descartada.
No entanto, estou observando que não há pacotes descartados para esse endereço IP que corresponda à cadeia fail2ban-apache-xmlrpc. Com certeza, eu verifico os logs do apache:
$ tail /var/log/apache2/other_vhosts_access.log
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:53 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:54 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:56 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:57 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:58 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:43:59 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:44:00 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
www.--SNIP--.com:80 80.82.70.239 - - [13/Jul/2013:02:44:02 +0000] "POST /xmlrpc.php HTTP/1.1" 403 474 "-" "-"
Não, não está sendo bloqueado! Eu também posso confirmar isso no log do fail2ban:
$ tail /var/log/fail2ban.log
2013-07-13 02:52:30,757 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:52:37,767 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:52:44,783 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:52:51,814 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:52:58,830 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:53:05,842 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:53:11,858 fail2ban.actions: WARNING [apache-xmlrpc] Unban 80.82.70.239
2013-07-13 02:53:12,910 fail2ban.actions: WARNING [apache-xmlrpc] Ban 80.82.70.239
2013-07-13 02:53:20,118 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
2013-07-13 02:53:27,129 fail2ban.actions: WARNING [apache-xmlrpc] 80.82.70.239 already banned
Ele continua aparecendo no log do apache e, portanto, o fail2ban está tentando continuar proibindo isso!
Eu honestamente não consigo descobrir por que a vida de mim é por que o iptables não está eliminando o tráfego desse endereço IP. A ordem das regras parece correta para mim, com o DROP vindo antes de qualquer outra coisa.
Eu tenho um monte de resultados do Google, onde as pessoas estão tendo um problema semelhante, mas parece sempre voltar a um problema que proíbe o tráfego SSH, onde eles estão em uma porta não padrão. No meu caso, estou apenas tentando banir um endereço IP na porta http padrão 80.
Espero que esteja negligenciando algo insanamente simples. Este é um VPS rodando o Ubuntu 12.04 no Linode. Se alguém tiver alguma idéia por favor me avise. Muito obrigado ...
EDITAR : Aqui está a saída de iptables -S
$ sudo iptables -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-N fail2ban-apache-xmlrpc
-N fail2ban-ssh
-A INPUT -p tcp -m multiport --dports 80,443 -j fail2ban-apache-xmlrpc
-A INPUT -p tcp -m multiport --dports 22 -j fail2ban-ssh
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT --reject-with icmp-port-unreachable
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
-A INPUT -j DROP
-A FORWARD -j DROP
-A OUTPUT -j ACCEPT
-A fail2ban-apache-xmlrpc -s 80.82.70.239/32 -j DROP
-A fail2ban-apache-xmlrpc -j RETURN
-A fail2ban-ssh -s 223.4.147.8/32 -j DROP
-A fail2ban-ssh -j RETURN