Como posso bloquear um tipo específico de ataque DDoS?

Question

Meu site está sendo atacado e está usando toda a RAM. Eu olhei para os logs do Apache e cada hit malicioso parece ser simplesmente uma solicitação POST em / , que nunca é requerida por um usuário normal.

Então, pensei e imaginei se há algum tipo de solução ou utilitário que monitore os logs do Apache e bloqueie todos os IPs que executam uma solicitação POST na raiz do site. Eu não estou familiarizado com a proteção contra DDoS e a pesquisa não parece me dar uma resposta, então vim para cá.

Obrigado.

Logs de exemplo:

103.3.221.202 - - [30/Sep/2012:16:02:03 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (iPad; CPU OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
122.72.80.100 - - [30/Sep/2012:16:02:03 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
122.72.28.15 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)"
210.75.120.5 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0"
122.96.59.103 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (Linux; U; Android 2.2; fr-fr; Desire_A8181 Build/FRF91) App3leWebKit/53.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1"
122.96.59.103 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (Linux; U; Android 2.2; fr-fr; Desire_A8181 Build/FRF91) App3leWebKit/53.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1"
122.72.124.3 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:13.0) Gecko/20100101 Firefox/13.0.1"
122.72.112.148 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.1" 302 485 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:13.0) Gecko/20100101 Firefox/13.0.1"
190.39.210.26 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.0" 302 485 "-" "Mozilla/5.0 (Windows NT 6.0; rv:13.0) Gecko/20100101 Firefox/13.0.1"
210.213.245.230 - - [30/Sep/2012:16:02:04 +0000] "POST / HTTP/1.0" 302 485 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)"
101.44.1.25 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (iPhone; CPU iPhone OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
101.44.1.28 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
101.44.1.28 - - [30/Sep/2012:16:02:14 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
103.3.221.202 - - [30/Sep/2012:16:02:13 +0000] "POST / HTTP/1.1" 302 466 "-" "Mozilla/5.0 (iPad; CPU OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
211.161.152.104 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"
101.44.1.25 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
101.44.1.25 - - [30/Sep/2012:16:02:11 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
211.161.152.105 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6"
211.161.152.105 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; MRA 5.8 (build 4157); .NET CLR 2.0.50727; AskTbPTV/5.11.3.15590)"
211.161.152.105 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; MRA 5.8 (build 4157); .NET CLR 2.0.50727; AskTbPTV/5.11.3.15590)"
101.44.1.25 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
101.44.1.25 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (iPhone; CPU iPhone OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
211.161.152.108 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (iPad; CPU OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
101.44.1.28 - - [30/Sep/2012:16:02:13 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
211.161.152.106 - - [30/Sep/2012:16:02:11 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:5.0.1) Gecko/20100101 Firefox/5.0.1"
103.3.221.202 - - [30/Sep/2012:16:02:13 +0000] "POST / HTTP/1.1" 302 466 "-" "Mozilla/5.0 (iPad; CPU OS 5_1_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B206 Safari/7534.48.3"
101.44.1.28 - - [30/Sep/2012:16:02:11 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
211.161.152.105 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; MRA 5.8 (build 4157); .NET CLR 2.0.50727; AskTbPTV/5.11.3.15590)"
211.161.152.104 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"
211.161.152.104 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"
211.161.152.105 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6"
101.44.1.25 - - [30/Sep/2012:16:02:10 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11"
122.72.124.2 - - [30/Sep/2012:16:02:17 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
122.72.124.2 - - [30/Sep/2012:16:02:11 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
122.72.124.2 - - [30/Sep/2012:16:02:17 +0000] "POST / HTTP/1.1" 302 522 "-" "Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1"
210.213.245.230 - - [30/Sep/2012:16:02:12 +0000] "POST / HTTP/1.0" 302 522 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)"

iptables -L :

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination   

-

bui@debian:~$ sudo iptables -I INPUT 1 -m string --algo bm --string 'Keep-Alive: 300' -j DROP
iptables: No chain/target/match by that name.
bui@debian:~$ sudo iptables -A INPUT -m string --algo bm --string 'Keep-Alive: 300' -j DROP
iptables: No chain/target/match by that name.

    

Answer 1

Use fail2ban . Você pode definir o padrão e ele fará com que as regras iptables concordem com isso.

    

Answer 2

Você pode ser atendido colocando um limite para evitar postar da raiz. Especialmente se "nunca é exigido por um usuário normal".

Em um .htconfig no seu diretório raiz:

<LimitExcept GET>
 Require valid-user
</LimitExcept>

O qual irá solicitar um usuário logado para qualquer método, mas um simples GET ( mais detalhes ). Ou se você quer apenas banir o POST no topo:

<Limit POST>
  Deny from all
</Limit>

Isto irá lançar uma mensagem proibida 403, que deve dizer aos scanners para não incomodar.

Para remover o limite, em um diretório em que você deseja permitir POST:

<Limit POST>
  Allow from all
</Limit>

    

Answer 3

Eu aconselho você a instalar o mod_security . Por favor, atualize sua pergunta com o tipo de sistema que você tem para que eu possa adicionar instruções sobre como instalá-lo.

Além disso, no firewall, pare os pacotes de ping recebidos.