题解
vlhub给了我们这样的网页

测试发现只不能提交.php文件,我们将一句话木马<?php phpinfo(); ?>写进1.txt,重命名为1.jpg,然后上传,这个过程burp抓包,将filename从"1.jpg"改为"1.jpg "并forward,上传成功~服务器存着一个叫"1.jpg "的非图片文件.

在浏览器输入62.234.14.252:8080/uploadfiles/1.jpgaa.php并抓包,

然后Forward,漏洞利用成功:

我的服务器是nginx1.20,比较新,上述漏洞未能成功显示phpinfo();显示如下:

踩坑点及深入挖掘原理
-
成功上传1.jpg[0x20]后,访问http://62.234.14.252:8080/uploadfiles/1.jpg显示如下

因为服务器上存的是1.jpg[0x20],而浏览器输入62.234.14.252:8080/uploadfiles/1.jpg[0x20]实际访问的还是62.234.14.252:8080/uploadfiles/1.jpg (对,浏览器会过滤忽略掉url开头结尾的空格),所以404了。
-
假设我们上传的就是1.jpg,文件名不带空格,然后我们访问62.234.14.252:8080/uploadfiles/1.jpg,这个访问过程无法被FoxyProxy和burp抓包,可能是因为纯图片不是报文不在其业务范围的缘故。
解决如何即访问1.jpg[0x20]又能让burp抓到包?:
访问http://62.234.14.252:8080/uploadfiles/1.jpgaa.php,违背了纯图片就能被抓包了。然后用burp在底层将aa修改为
[0x20][0x00]就能访问1.jpg[0x20]了 -
官方教程教收尾阶段访问
http://your-ip:8080/uploadfiles/1.jpg[0x20][0x00].php,我傻乎乎的尝试在浏览器输入带[]的、不带[]的、[0x20]改写而成空格的、[0x00]改写不成空,都显示404了。后来才知道要去burp去修改报文的十六进制底层,即访问http://62.234.14.252:8080/uploadfiles/1.jpgaa.php,其中aa是可以留的占位符,a在底层对应ascii的十六进制61,将[61][61]改成[20][00],其中20是空格,00是空的ascii。 -
这里应该是用到了0x00截断原理了,具体原理是 系统在对文件名的读取时,如果遇到0x00,就会认为读取已结束。这个常用在对文件类型名的绕过上。还不止这个原理。
-
当Nginx得到一个用户请求时,首先对url进行解析,进行正则匹配,如果匹配到以.php后缀结尾的文件名(即http://62.234.14.252:8080/uploadfiles/1.jpg \0.php),会将请求的PHP文件交给PHP-CGI去解析。
其中处理模块如下:location ~ \.php$ { root html; include fastcgi_params; fastcgi_pass IP:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /var/www/html$fastcgi_script_name; fastcgi_param DOCUMENT_ROOT /var/www/html; }
以.php结尾的文件都会交给该模块处理,其中fastcgi_pass就是Nginx与PHP-FPM之间的媒介,通过ip+port的方式将请求转发给PHP解释器。但是我们有代码的文件它叫’1.jpg ‘啊,不叫'1.php'不叫'1.jpg php'不叫'1.jpgphp',所以我们利用0x00的阶段原理,用0x00将'1.jpg '和.php分隔开。http://62.234.14.252:8080/uploadfiles/1.jpg \0.php通过.php进入这个Location块;但进入后,Nginx却因0x00隔断而错误地认为请求的文件是
1.gif[0x20],就将'1.gif '交付PHP-CGI去解析(就设置其为SCRIPT_FILENAME
Fobertenete
Hi I am so grateful I found your weblog, I really found you by accident, while I was browsing on Bing for something else, Anyways I am here now and would just like to say kudos for a remarkable post and a all round entertaining blog (I also love the theme/design), I dont have time to look over it all at the moment but I have saved it and also added in your RSS feeds, so when I have time I will be back to read a great deal more, Please do keep up the awesome job.
https://graal.org.ua/pichka-dlia-far-shcho-obraty-dlia-nevelykoi-maisterni.html
jogoriogem 744
O caca-niqueis <a href=https://jogoriogems.com/>Rio Gems slot</a> combina a nostalgia classica com o dinamismo de um parque de diversoes: multiplicadores, giros gratis, re-spins e Wilds aleatorios. Apresenta graficos coloridos, uma interface responsiva e uma versao demo para praticar. Ao jogar, lembre-se de se manter seguro: estabeleca limites e faca pausas.
onewinner 211
Любите классику? <a href=https://onewinner.sbs/>фрукты слоты</a> с семёрками, BAR и цитрусами дарит частые хиты, Wild, Scatter и бонусные вращения. Демо-режим бесплатно, честный RTP, адаптация под смартфоны. Простые правила и динамичный геймплей — отличный выбор для новичков и профи. Помните о разумных лимитах.
jogolegacyofdead 751
Jogue o caca-niqueis <a href=https://jogolegacyofdead.com/>Legacy of Dead</a>: tumbas antigas, riscos e giros gratis com simbolos expansivos. Modo de demonstracao sem cadastro, RTP justo, simbolos Wild/Scatter, multiplicadores e rodadas bonus. Otimizado para dispositivos moveis, depositos e saques praticos, dicas para iniciantes.
Davidjal
Click to learn more: <a href=https://www.atrium-patrimoine.com/>https://www.atrium-patrimoine.com</a>
Waltersix
Читайте больше на сайте: <a href=https://badgerboats.ru/>https://badgerboats.ru</a>
Randyevoto
Всё самое новое тут: <a href=https://it-on.ru/>https://it-on.ru</a>
narkologicheskaya klinika_zzon
наркология <a href=http://narkologicheskaya-klinika-24.ru>наркология</a> .
ShaneBup
WOW just what I was looking for. Came here by searching for %meta_keyword%
https://klub-saigorkz.ucoz.net/forum/25-3764-1
narkologicheskaya klinika_gnon
зашиваться от алкоголя <a href=https://narkologicheskaya-klinika-24.ru/>https://narkologicheskaya-klinika-24.ru/</a> .