20个Nginx Web服务器最佳安全实践

# /usr/local/nginx/sbin/nginx –t 

the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok

configuration file /usr/local/nginx/conf/nginx.conf test is successful

# /usr/local/nginx/sbin/nginx -s reload 

# /usr/local/nginx/sbin/nginx -s stop 

getsebool -a | less

getsebool -a | grep off

getsebool -a | grep o

LABEL=/nginx     

/nginx          

ext3   

defaults,nosuid,noexec,nodev 1 2

# 避免放大攻击

net.ipv4.icmp_echo_ignore_broadcasts = 1

# 开启恶意icmp错误消息保护

net.ipv4.icmp_ignore_bogus_error_responses = 1

# 开启SYN洪水攻击保护

net.ipv4.tcp_syncookies = 1

# 开启并记录欺骗，源路由和重定向包

net.ipv4.conf.all.log_martians = 1

net.ipv4.conf.default.log_martians = 1

# 处理无源路由的包

net.ipv4.conf.all.accept_source_route = 0

net.ipv4.conf.default.accept_source_route = 0       
       
# 开启反向路径过滤

net.ipv4.conf.all.rp_filter = 1

net.ipv4.conf.default.rp_filter = 1

# 确保无人能修改路由表

net.ipv4.conf.all.accept_redirects = 0

net.ipv4.conf.default.accept_redirects = 0

net.ipv4.conf.all.secure_redirects = 0

net.ipv4.conf.default.secure_redirects = 0

# 不充当路由器

net.ipv4.ip_forward = 0

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

# 开启execshild

kernel.exec-shield = 1

kernel.randomize_va_space = 1

# IPv6设置

net.ipv6.conf.default.router_solicitations = 0

net.ipv6.conf.default.accept_ra_rtr_pref = 0

net.ipv6.conf.default.accept_ra_pinfo = 0

net.ipv6.conf.default.accept_ra_defrtr = 0

net.ipv6.conf.default.autoconf = 0

net.ipv6.conf.default.dad_transmits = 0

net.ipv6.conf.default.max_addresses = 1

# 优化LB使用的端口

# 增加系统文件描述符限制

fs.file-max = 65535

# 允许更多的PIDs (减少滚动翻转问题); may break some programs 32768

kernel.pid_max = 65536

# 增加系统IP端口限制

net.ipv4.ip_local_port_range = 2000 65000

# 增加TCP最大缓冲区大小

net.ipv4.tcp_rmem = 4096 87380 8388608

net.ipv4.tcp_wmem = 4096 87380 8388608

# 增加Linux自动调整TCP缓冲区限制

# 最小，默认和最大可使用的字节数

# 最大值不低于4MB，如果你使用非常高的BDP路径可以设置得更高

# Tcp窗口等

net.core.rmem_max = 8388608

net.core.wmem_max = 8388608

net.core.netdev_max_backlog = 5000

net.ipv4.tcp_window_scaling = 1

# ./configure --without-http_autoindex_module --without-http_ssi_module

# make

# make install

       
# ./configure --help | less
       
       

# vi +48 src/http/ngx_http_header_filter_module.c 

static char ngx_http_server_string[] = "Server: nginx" CRLF;

static char ngx_http_server_full_string[] = "Server: " NGINX_VER CRLF;

static char ngx_http_server_string[] = "Server: Ninja Web Server" CRLF;

static char ngx_http_server_full_string[] = "Server: Ninja Web Server" CRLF;

server_tokens off

# yum -y install selinux-policy-targeted selinux-policy-devel

# cd /opt

# wget 'http://downloads.sourceforge.net/project/selinuxnginx/se-ngix_1_0_10.tar.

gz?use_mirror=nchc'

# tar -zxvf se-ngix_1_0_10.tar.gz 

# cd se-ngix_1_0_10/nginx

# make

Compiling targeted nginx module

/usr/bin/checkmodule:  loading policy configuration from tmp/nginx.tmp

/usr/bin/checkmodule:  policy configuration loaded

/usr/bin/checkmodule:  writing binary representation (version 6) to tmp/nginx.mod

Creating targeted nginx.pp policy package

rm tmp/nginx.mod.fc tmp/nginx.mod

       
# /usr/sbin/semodule -i nginx.pp
       
       

#!/bin/bash

IPT="/sbin/iptables"

#### IPS ######

# 获得服务器公共IP

SERVER_IP=$(ifconfig eth0 | grep 'inet addr:' | awk -F'inet addr:' '{ print $2}' | awk '{ print $1}')

LB1_IP="204.54.1.1"

LB2_IP="204.54.1.2"

# 实现某些智能逻辑，以便我们可以在LB2上使用damm脚本

OTHER_LB=""

SERVER_IP=""

[[ "$SERVER_IP" == "$LB1_IP" ]] && OTHER_LB="$LB2_IP" || OTHER_LB="$LB1_IP"

[[ "$OTHER_LB" == "$LB2_IP" ]] && OPP_LB="$LB1_IP" || OPP_LB="$LB2_IP"

### IPs ###

PUB_SSH_ONLY="122.xx.yy.zz/29" #### 文件 #####

BLOCKED_IP_TDB=/root/.fw/blocked.ip.txt

SPOOFIP="127.0.0.0/8 192.168.0.0/16 172.16.0.0/12 10.0.0.0/8 169.254.0.0/16 0.0.0.0/8 240.0.0.0/4 255.255.255.255/32 168.254.0.0/16 224.0.0.0/4 240.0.0.0/5 248.0.0.0/5 192.0.2.0/24"

BADIPS=$( [[ -f ${BLOCKED_IP_TDB} ]] && egrep -v "^#|^$" ${BLOCKED_IP_TDB})

### 接口 ###

PUB_IF="eth0"   # public interface

LO_IF="lo"      # loopback

VPN_IF="eth1"   # vpn / private net

### 启动防火墙 ###

echo "Setting LB1 $(hostname) Firewall..."

# 删除和关闭一切

$IPT -P INPUT DROP

$IPT -P OUTPUT DROP

$IPT -P FORWARD DROP

# 不受限制的lo访问

$IPT -A INPUT -i ${LO_IF} -j ACCEPT

$IPT -A OUTPUT -o ${LO_IF} -j ACCEPT

# 不受限制的vpn/pnet访问

$IPT -A INPUT -i ${VPN_IF} -j ACCEPT

$IPT -A OUTPUT -o ${VPN_IF} -j ACCEPT

# 删除sync

$IPT -A INPUT -i ${PUB_IF} -p tcp ! --syn -m state --state NEW -j DROP

# 删除碎片

$IPT -A INPUT -i ${PUB_IF} -f -j DROP

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL ALL -j DROP

# 删除空包

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL NONE -m limit --limit 5/m --limit-burst 7 -j LOG --log-prefix " NULL Packets "

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL NONE -j DROP

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,RST SYN,RST -j DROP

# 删除XMAS

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,FIN SYN,FIN -m limit --limit 5/m --limit-burst 7 -j LOG --log-prefix " XMAS Packets "

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP

# 删除FIN包扫描

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags FIN,ACK FIN -m limit --limit 5/m --limit-burst 7 -j LOG --log-prefix " Fin Packets Scan "

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags FIN,ACK FIN -j DROP

$IPT  -A INPUT -i ${PUB_IF} -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP

# 记录并放弃广播/多播和无效数据包

$IPT  -A INPUT -i ${PUB_IF} -m pkttype --pkt-type broadcast -j LOG --log-prefix " Broadcast "

$IPT  -A INPUT -i ${PUB_IF} -m pkttype --pkt-type broadcast -j DROP

$IPT  -A INPUT -i ${PUB_IF} -m pkttype --pkt-type multicast -j LOG --log-prefix " Multicast "

$IPT  -A INPUT -i ${PUB_IF} -m pkttype --pkt-type multicast -j DROP

$IPT  -A INPUT -i ${PUB_IF} -m state --state INVALID -j LOG --log-prefix " Invalid "

$IPT  -A INPUT -i ${PUB_IF} -m state --state INVALID -j DROP

# 记录和阻止欺骗IP

$IPT -N spooflist

for ipblock in $SPOOFIP

do    

$IPT -A spooflist -i ${PUB_IF} -s $ipblock -j LOG --log-prefix " SPOOF List Block "       

$IPT -A spooflist -i ${PUB_IF} -s $ipblock -j DROP

done

$IPT -I INPUT -j spooflist

$IPT -I OUTPUT -j spooflist

$IPT -I FORWARD -j spooflist

# 只允许从选定的公共IP使用SSH

for ip in ${PUB_SSH_ONLY}

do        $IPT -A INPUT -i ${PUB_IF} -s ${ip} -p tcp -d ${SERVER_IP} --destination-port 22 -j ACCEPT       

$IPT -A OUTPUT -o ${PUB_IF} -d ${ip} -p tcp -s ${SERVER_IP} --sport 22 -j ACCEPT

done

# 允许入站ICMP ping

$IPT -A INPUT -i ${PUB_IF} -p icmp --icmp-type 8 -s 0/0 -m state --state NEW,ESTABLISHED,RELATED -m limit --limit 30/sec  -j ACCEPT

$IPT -A OUTPUT -o ${PUB_IF} -p icmp --icmp-type 0 -d 0/0 -m state --state ESTABLISHED,RELATED -j ACCEPT

# 允许入站HTTP端口80

$IPT -A INPUT -i ${PUB_IF} -p tcp -s 0/0 --sport 1024:65535 --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

$IPT -A OUTPUT -o ${PUB_IF} -p tcp --sport 80 -d 0/0 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT

# 允许出站NTP

$IPT -A OUTPUT -o ${PUB_IF} -p udp --dport 123 -m state --state NEW,ESTABLISHED -j ACCEPT

$IPT -A INPUT -i ${PUB_IF} -p udp --sport 123 -m state --state ESTABLISHED -j ACCEPT

# 允许出站SMTP

$IPT -A OUTPUT -o ${PUB_IF} -p tcp --dport 25 -m state --state NEW,ESTABLISHED -j ACCEPT

$IPT -A INPUT -i ${PUB_IF} -p tcp --sport 25 -m state --state ESTABLISHED -j ACCEPT

### 在这里添加其他规则 ####

#######################

# 删除并记录其它数据包

$IPT -A INPUT -m limit --limit 5/m --limit-burst 7 -j LOG --log-prefix " DEFAULT DROP "

$IPT -A INPUT -j DROP

exit 0

# vi /usr/local/nginx/conf/nginx.conf 

## Start: Size Limits & Buffer Overflows ##  client_body_buffer_size  1K;       
       
client_header_buffer_size 1k;  client_max_body_size 1k;  large_client_header_buffers 2 1k; 

## END: Size Limits & Buffer Overflows ##

## Start: Timeouts 

##  client_body_timeout   

10;  client_header_timeout 10;       
       
keepalive_timeout     

5 5;  send_timeout          

10;

## End: Timeouts ##

### Directive describes the zone, in which the session states are stored i.e. store in slimits. 

### 1m can handle 32000 sessions with 32 bytes/session, set to 5m x 32000 session ###       
       
limit_zone slimits $binary_remote_addr 5m;       
       
### Control maximum number of simultaneous connections for one session i.e. ###

### restricts the amount of connections from a single ip address ###

limit_conn slimits 5;

## Only requests to our Host are allowed i.e. nixcraft.in, images.nixcraft.in and www.nixcraft.in   

if ($host !~ ^(nixcraft.in|www.nixcraft.in|images.nixcraft.in)$ ) {         

return 444;      }

##

## Only allow these request methods ##     

if ($request_method !~ ^(GET|HEAD|POST)$ ) {         

return 444;     }

## Do not accept DELETE, SEARCH and other methods ##

## Block download agents ##     

if ($http_user_agent ~* LWP::Simple|BBBike|wget) {         

return 403;     }

##

## Block some robots ##     

if ($http_user_agent ~* msnbot|scrapbot) {           

return 403;     }

## Deny certain Referers ###   

if ( $http_referer ~* (babes|forsale|girl|jewelry|love|nudit|organic|poker|porn|sex|teen) )     

{        

# return 404;        

return 403;     }

##

# Stop deep linking or hot linking

location /images/ {  valid_referers none blocked www.example.com example.com;   

if ($invalid_referer) {     

return   403;   }

}

valid_referers blocked www.example.com example.com; 

if ($invalid_referer) { rewrite ^/images/uploads.*\.(gif|jpg|jpeg|png)$ 

http://www.examples.com/banned.jpg last

}

location /docs/ {  ## block one workstation  deny    192.168.1.1;

## allow anyone in 192.168.1.0/24  allow   192.168.1.0/24;

## drop rest of the world  deny    all;

}

# mkdir /usr/local/nginx/conf/.htpasswd/

# htpasswd -c /usr/local/nginx/conf/.htpasswd/passwd vivek

### Password Protect /personal-images/ and /delta/ directories ###

location ~ /(personal-images/.*|delta/.*) {  auth_basic  "Restricted";  

auth_basic_user_file   /usr/local/nginx/conf/.htpasswd/passwd;

}

# htpasswd -s /usr/local/nginx/conf/.htpasswd/passwd userName 

# cd /usr/local/nginx/conf

# openssl genrsa -des3 -out server.key 1024

# openssl req -new -key server.key -out server.csr

# cp server.key server.key.org

# openssl rsa -in server.key.org -out server.key

# openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

server {    

server_name example.com;    

listen 443;    

ssl on;    

ssl_certificate /usr/local/nginx/conf/server.crt;    

ssl_certificate_key /usr/local/nginx/conf/server.key;    

access_log /usr/local/nginx/logs/ssl.access.log;    

error_log /usr/local/nginx/logs/ssl.error.log;

# /usr/local/nginx/sbin/nginx -s reload 

# 禁用危险的函数

disable_functions = phpinfo, system, mail, exec

## 限制资源  ##

# 每个脚本的最大执行时间，单位秒

max_execution_time = 30

# 每个脚本解析请求数据的最大时间

max_input_time = 60

# 每个脚本可以消耗的最大内存（8MB）

memory_limit = 8M

# PHP要接收的POST数据最大大小

post_max_size = 8M

# 是否允许HTTP文件上传

file_uploads = Off

# 允许上传的最大文件大小

upload_max_filesize = 2M

# 不将PHP错误消息暴露给外部用户

display_errors = Off

# 启用安全模式

safe_mode = On

# 只允许访问隔离目录中的可执行文件

safe_mode_exec_dir = php-required-executables-path

# 限制外部访问PHP资源

safe_mode_allowed_env_vars = PHP_

# 限制泄露PHP信息

expose_php = Off

# 记录所有错误

log_errors = On

# 不为输入数据注册全局

register_globals = Off

# 最小化允许的php post大小

post_max_size = 1K

# 确保PHP重定向正确

cgi.force_redirect = 0

# 禁止上传，除非必要

file_uploads = Off

# 启用SQL安全模式

sql.safe_mode = On

# 避免打开远程文件

allow_url_fopen = Off

/sbin/iptables -A INPUT -p tcp --dport 80 -i eth0 -m state --state NEW -m recent --set

/sbin/iptables -A INPUT -p tcp --dport 80 -i eth0 -m state --state NEW -m recent 

--update --seconds 60  --hitcount 15 -j DROP

service iptables save

ebserver_ip="202.54.1.1"

table  persist

block in quick from 

pass in on $ext_if proto tcp to $webserver_ip port www flags S/SA keep state (max-src-conn 100, 

max-src-conn-rate 15/5, overload  flush)

# find /nginx -user nginx

# find /usr/local/nginx/html -user nginx

# ls -l /usr/local/nginx/html/ 

-rw-r--r-- 1 root root 925 Jan  3 00:50 error4xx.html

-rw-r--r-- 1 root root  52 Jan  3 10:00 error5xx.html

-rw-r--r-- 1 root root 134 Jan  3 00:52 index.html

# find /nginx -name '.?*' -not -name .ht* -or -name '*~' -or -name '*.bak*' -or -name '*.old*'

# find /usr/local/nginx/html/ -name '.?*' -not -name .ht* -or -name '*~' 

-or -name '*.bak*' -or -name '*.old*'

/sbin/iptables -A OUTPUT -o eth0 -m owner --uid-owner vivek -p tcp 

--dport 80 -m state --state NEW,ESTABLISHED  -j ACCEPT

# grep "/login.php??" /usr/local/nginx/logs/access_log

# grep "...etc/passwd" /usr/local/nginx/logs/access_log

# egrep -i "denied|error|warn" /usr/local/nginx/logs/error_log