转自：http://www.tuicool.com/articles/FbQ3ymB
WAF的主要功能为：
- ip黑白名单
- url黑白名单
- useragent黑白名单
- referer黑白名单
- 常见web漏洞防护，如xss，sql注入等
- cc攻击防护
- 扫描器简单防护
- 其他你想要的功能
WAF的总体检测思路：
- 当用户访问到nginx时，waf首先获取用户的ip，uri，referer，useragent，，cookie，args，post，method，header信息。
- 将获取到的信息依次传给上述功能的函数，如ip规则，在ip规则中，循环到所有的ip规则，如果匹配到ip则根据规则的处理方式来进行处理，匹配到之后不继续匹配后续规则。
- 需要开启的功能依次在主函数中调用即可，顺序也可根据实际场景来确定最合适的顺序。
config.lua
RulePath = "/data/mypro/ngx_lua/waf/wafconf/"
attacklog = "on"
logdir = "/usr/local/openresty/nginx/logs"
UrlDeny="on"
Redirect="on"
CookieMatch="on"
postMatch="on"
whiteModule="on"
ipWhitelist={}
ipBlocklist={"1.0.0.1"}
CCDeny="off"
CCrate="100/60"
html=[[Please go away~~ ]]
init.lua
require ‘config‘
local match = string.match
local ngxmatch=ngx.re.match
local unescape=ngx.unescape_uri
local get_headers = ngx.req.get_headers
local optionIsOn = function (options) return options == "on" and true or false end
logpath = logdir
rulepath = RulePath
UrlDeny = optionIsOn(UrlDeny)
PostCheck = optionIsOn(postMatch)
CookieCheck = optionIsOn(cookieMatch)
WhiteCheck = optionIsOn(whiteModule)
PathInfoFix = optionIsOn(PathInfoFix)
attacklog = optionIsOn(attacklog)
CCDeny = optionIsOn(CCDeny)
Redirect=optionIsOn(Redirect)
function getClientIp()
IP = ngx.req.get_headers()["X-Real-IP"]
if IP == nil then
IP = ngx.var.remote_addr
end
if IP == nil then
IP = "unknown"
end
return IP
end
function write(logfile,msg)
local fd = io.open(logfile,"ab")
if fd == nil then return end
fd:write(msg)
fd:flush()
fd:close()
end
function log(method,url,data,ruletag)
if attacklog then
local realIp = getClientIp()
local ua = ngx.var.http_user_agent
local servername=ngx.var.server_name
local time=ngx.localtime()
if ua then
line = realIp.." ["..time.."] \""..method.." "..servername..url.."\" \""..data.."\" \""..ua.."\" \""..ruletag.."\"\n"
else
line = realIp.." ["..time.."] \""..method.." "..servername..url.."\" \""..data.."\" - \""..ruletag.."\"\n"
end
local filename = logpath..‘/‘..servername.."_"..ngx.today().."_sec.log"
write(filename,line)
end
end
------------------------------------规则读取函数-------------------------------------------------------------------
function read_rule(var)
file = io.open(rulepath..‘/‘..var,"r")
if file==nil then
return
end
t = {}
for line in file:lines() do
table.insert(t,line)
end
file:close()
return(t)
end
local urlrules=read_rule(‘url‘)
local argsrules=read_rule(‘args‘)
local uarules=read_rule(‘user-agent‘)
local wturlrules=read_rule(‘whiteurl‘)
local postrules=read_rule(‘post‘)
local ckrules=read_rule(‘cookie‘)
function say_html()
if Redirect then
ngx.header.content_type = "text/html"
ngx.say(html)
ngx.exit(200)
end
end
function whiteurl()
if WhiteCheck then
if wturlrules ~=nil then
for _,rule in pairs(wturlrules) do
if ngxmatch(ngx.var.request_uri,rule,"imjo") then
return true
end
end
end
end
return false
end
function args()
for _,rule in pairs(argsrules) do
local args = ngx.req.get_uri_args()
for key, val in pairs(args) do
if type(val)==‘table‘ then
if val == false then
data=table.concat(val, " ")
end
else
data=val
end
if data and type(data) ~= "boolean" and rule ~="" and ngxmatch(unescape(data),rule,"imjo") then
log(‘GET‘,ngx.var.request_uri,"-",rule)
say_html()
return true
end
end
end
return false
end
function url()
if UrlDeny then
for _,rule in pairs(urlrules) do
if rule ~="" and ngxmatch(ngx.var.request_uri,rule,"imjo") then
log(‘GET‘,ngx.var.request_uri,"-",rule)
say_html()
return true
end
end
end
return false
end
function ua()
local ua = ngx.var.http_user_agent
if ua ~= nil then
for _,rule in pairs(uarules) do
if rule ~="" and ngxmatch(ua,rule,"imjo") then
log(‘UA‘,ngx.var.request_uri,"-",rule)
say_html()
return true
end
end
end
return false
end
function body(data)
for _,rule in pairs(postrules) do
if rule ~="" and data~="" and ngxmatch(unescape(data),rule,"imjo") then
log(‘POST‘,ngx.var.request_uri,data,rule)
say_html()
return true
end
end
return false
end
function cookie()
local ck = ngx.var.http_cookie
if CookieCheck and ck then
for _,rule in pairs(ckrules) do
if rule ~="" and ngxmatch(ck,rule,"imjo") then
log(‘Cookie‘,ngx.var.request_uri,"-",rule)
say_html()
return true
end
end
end
return false
end
function denycc()
if CCDeny then
local uri=ngx.var.uri
CCcount=tonumber(string.match(CCrate,‘(.*)/‘))
CCseconds=tonumber(string.match(CCrate,‘/(.*)‘))
local token = getClientIp()..uri
local limit = ngx.shared.limit
local req,_=limit:get(token)
if req then
if req > CCcount then
ngx.exit(503)
return true
else
limit:incr(token,1)
end
else
limit:set(token,1,CCseconds)
end
end
return false
end
function get_boundary()
local header = get_headers()["content-type"]
if not header then
return nil
end
if type(header) == "table" then
header = header[1]
end
local m = match(header, ";%s*boundary=\"([^\"]+)\"")
if m then
return m
end
return match(header, ";%s*boundary=([^\",;]+)")
end
function whiteip()
if next(ipWhitelist) ~= nil then
for _,ip in pairs(ipWhitelist) do
if getClientIp()==ip then
return true
end
end
end
return false
end
function blockip()
if next(ipBlocklist) ~= nil then
for _,ip in pairs(ipBlocklist) do
if getClientIp()==ip then
ngx.exit(403)
return true
end
end
end
return false
end
waf.lua
local content_length=tonumber(ngx.req.get_headers()[‘content-length‘])
local method=ngx.req.get_method()
if whiteip() then
elseif blockip() then
elseif denycc() then
elseif ngx.var.http_Acunetix_Aspect then
ngx.exit(444)
elseif ngx.var.http_X_Scan_Memo then
ngx.exit(444)
elseif whiteurl() then
elseif ua() then
elseif url() then
elseif args() then
elseif cookie() then
elseif PostCheck then
if method=="POST" then
local boundary = get_boundary()
if boundary then
local len = string.len
local sock, err = ngx.req.socket()
if not sock then
return
end
ngx.req.init_body(128 * 1024)
sock:settimeout(0)
local content_length = nil
content_length=tonumber(ngx.req.get_headers()[‘content-length‘])
local chunk_size = 4096
if content_length < chunk_size then
chunk_size = content_length
end
local size = 0
while size < content_length do
local data, err, partial = sock:receive(chunk_size)
data = data or partial
if not data then
return
end
ngx.req.append_body(data)
if body(data) then
return true
end
size = size + len(data)
local less = content_length - size
if less < chunk_size then
chunk_size = less
end
end
ngx.req.finish_body()
else
ngx.req.read_body()
local args = ngx.req.get_post_args()
if not args then
return
end
for key, val in pairs(args) do
if type(val) == "table" or val == false then
data=table.concat(val, ", ")
else
data=val
end
if data and type(data) ~= "boolean" and body(data) then
return true
end
end
end
end
else
return
end
在nginx.conf的http段添加
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;
重启nginx
部署完毕可以尝试如下命令：
curl http://xxxx/test.php?id=../etc/passwd 返回"Please go away~~"字样，说明规则生效。
时间： 2024-10-02 07:10:40