利用 nginx_lua 定制高效灵活的专属WAF

0x01 什么是Lua

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关于Lua,就不用多说了吧,想必朋友们应该也都非常熟悉了,众多脚本语言中的一种,不过相对于其它脚本来说,性能要略高一点
在nginx中也提供了一个nginx_lua的模块,主要是为了方便用户,可以灵活的通过lua来扩展nginx功能,比如lua_waf
有兴趣可自行深入了解,这里就不细说了,我们今天的重点主要还是想利用它来快速部署一个简易版的Waf

0x02 这里,我还是拿之前已经编译好的lnmp环境来演示,因为等会儿要重新编译nginx,所以就直接把之前nginx的整个安装目录干掉,因为是源码编译安装的,所以也不会有啥残留[源码编译安装的好处],记得在干掉之前先把nginx服务停掉,配置文件[nginx.conf]也备份一下,方便等会儿再直接拿过来用

1	php5.5.38 + mysql-5.5.32 + nginx-1.12.1 + centOS6.8_x64

 pkill nginx
 netstat -tulnp | grep "80"
 cp /usr/local/nginx/conf/nginx.conf /root/
 cp /usr/local/nginx/conf/extra/bwapp.conf /root/

0x03 准备好所需的所有源码包,注意,这里的nginx尽量先不要用太高的版本,高版本自身还有些问题,在实际编译时错误的解决也比较周折,暂不推荐用

LuaJIT-2.0.5.tar.gz				
lua-nginx-module-0.9.13.tar.gz
ngx_devel_kit-0.2.19.tar.gz
nginx-1.8.1.tar.gz

0x04 编译安装 LuaJIT ,lua脚本的解释器,因为这里是64位系统,防止等会儿找不到库,所以就提前把它链到32位的库中

 tar xf LuaJIT-2.0.5.tar.gz
# cd LuaJIT-2.0.5
# make && make install
# ln -s /usr/local/lib/libluajit-5.1.so.2 /lib64/libluajit-5.1.so.2
# echo "LUAJIT_LIB=/usr/local/lib" >> /etc/profile
# echo "LUAJIT_INC=/usr/local/include/luajit-2.0/" >> /etc/profile
# source /etc/profile

0x05 重新编译安装nginx,其实,我自己这里的依赖库本身是不用再装的,因为之前装nginx时已经都装过了,如果你是第一次全新安装nginx,可能还是要装一下

# wget http://nginx.org/download/nginx-1.8.1.tar.gz
# yum install pcre pcre-devel openssl openssl-devel -y
# useradd -s /sbin/nologin -M nginx
# tar xf ../lua-nginx-module-0.9.16.tar.gz
# tar xf ../ngx_devel_kit-0.2.19.tar.gz
# tar xf nginx-1.8.1.tar.gz
# cd nginx-1.8.1
# ./configure --prefix=/usr/local/nginx-1.8.1 --user=nginx --group=nginx --with-http_ssl_module --with-http_stub_status_module --with-http_gzip_static_module --with-file-aio --with-http_dav_module --add-module=./lua-nginx-module-0.9.16 --add-module=./ngx_devel_kit-0.2.19/
# make && make install
# ln -s /usr/local/nginx-1.8.1/ /usr/local/nginx
# cd /usr/local/nginx/conf/
# mv nginx.conf nginx.conf.bak && egrep -v "^$|#" nginx.conf.bak >> nginx.conf

0x06 重新配置nginx,在nginx中配置文件中加入以下语句,之后重启nginx,主要是为了测试lua是否可用


http {
    .....
    log_format main '$remote_addr - $remote_user  [$time_local]  '
    ' "$request" $request_body $status  $body_bytes_sent  '
    ' "$http_referer"  "$http_user_agent"  "$http_x_forwarded_for" ';
	
    server {
    ....
        location /lua {
            default_type 'text/plain';
            content_by_lua 'ngx.say("Lua say Hello to you!")';
        }
    ....
    }
    .....
}
# /usr/local/nginx-1.8.1/sbin/nginx -t
# /usr/local/nginx-1.8.1/sbin/nginx

0x07 在nginx主配置文件中加载lua_waf,具体配置如下

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# git clone https://github.com/loveshell/ngx_lua_waf.git
# cp -r ngx_lua_waf/ /usr/local/nginx/conf/waf
# cd /usr/local/nginx/conf/

# vi nginx.conf
http {
	....
    lua_package_path "/usr/local/nginx/conf/waf/?.lua";
    lua_shared_dict limit 10m;
    init_by_lua_file  /usr/local/nginx/conf/waf/init.lua;
    access_by_lua_file /usr/local/nginx/conf/waf/waf.lua;
	....
	
	log_format main '$remote_addr - $remote_user  [$time_local]  '
    ' "$request" $request_body $status  $body_bytes_sent  '
    ' "$http_referer"  "$http_user_agent"  "$http_x_forwarded_for" "$dm_cookie" ';
	
	include extra/bwapp.conf;
}

0x08 编辑waf配置,非常简单,从名字都能看出来是干啥的,非常简单

1	# vi /usr/local/nginx/conf/waf/config.lua

RulePath = "/usr/local/nginx/conf/waf/wafconf/"
attacklog = "on"		# 开启日志记录
logdir = "/usr/local/nginx/logs/hack/"
UrlDeny="on"			# 从url中拦截
Redirect="on"
CookieMatch="on"		# 从cookie中拦截
postMatch="on"			# 从post包中拦截
whiteModule="on"
black_fileExt={"php","jsp"}	# 黑名单后缀
ipWhitelist={"127.0.0.1"}	# ip白名单
ipBlocklist={"1.0.0.1"}		# ip黑名单
CCDeny="on"			# 开启防CC攻击
CCrate="100/60"
html=[[
<center><h1>No sir! </h1></center>
]]

# mkdir /usr/local/nginx/logs/hack/
# chown -R nginx.nginx /usr/local/nginx/logs/hack/	注意,这里一定要nginx可写,不然你会发现拦截不了,因为log文件根本没法创建
# mkdir /usr/local/nginx-1.8.1/conf/extra
# cp bwapp.conf /usr/local/nginx/conf/extra/
# /usr/local/nginx/sbin/nginx -t
# /usr/local/nginx/sbin/nginx -s reload