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WordPress Plugin - AutoSuggest sql注入

一、漏洞简介

WP AutoSuggest这款插件在访问者输入关键字时,插件会在提交搜索查询之前通过AJAX请求在网页中显示一些建议。访问者可以通过按Enter继续搜索,或者访问者可以使用键盘箭头直接访问建议的帖子。

二、漏洞影响

三、复现过程

首先我们得进入exploit-db网站上下载这个存在漏洞的版本的插件原始码和本地构建WordPress网站(本地构建WordPress这里就不说了)。下载源码,如下图所示

下载完成之后,把wp-autosuggest目录直接拖到Wordpress目录的\wp-content\plugins\下。

接着,登录后台,启用这款插件,如下图所示:

启用后,退出后台,如下图所示:

然后根据exploit-db网站上给出的漏洞详情,我们访问下面的URL:

http://www.0-sec.org/wp-content/plugins/wp-autosuggest/autosuggest.php?wpas_action=query&wpas_keys=1

访问后,网页内容如下图所示:

根据exploit-db网站上给出的漏洞详情,我们也知道了wpas_keys参数存在注入,于是我们可以使用SQLMAP注入神器,对网站进行注入。SQLMAP命令如下:

sqlmap.py -u "http://www.0-sec.org/wp-content/plugins/wp-autosuggest/autosuggest.php?wpas_action=query&wpas_keys=1*" --technique BT --dbms MYSQL --risk 3 --level 5 --tamper space2comment

一开始,笔者使用的时php5.2.17+Apache的环境,结果复现不了,头疼了半天,如下图:

后来笔者换了一个php-5.4.45+Apache的环境,就解决了。

通过SQLMAP,成功获取到服务器的一些信息,如下图所示:

下图也成功跑出了当前数据库的名称。

漏洞分析

分析WordPress插件的话还是挺容易的。文件和代码也不是很多,用Notepad++就够用啦。进入插件根目录下面就看到了autosuggest_functions.php、autosuggest.php这两个php文件。

下面是autosuggest.php文件所有代码:

<?php
include 'autosuggest_functions.php';

$wpas_action = '';
$wpas_keys = '';
if(isset($_GET['wpas_action'])) {
    $wpas_action = $_GET['wpas_action'];
}
if (isset($_GET['wpas_keys'])) {
    $wpas_keys = $_GET['wpas_keys'];
}


if ($wpas_action == 'query') {

    require_once ('../../../wp-config.php');

    header('Content-Type: text/xml');
    echo '<results>';

    global $wpdb;

    $wpas_keys = str_replace(' ','%',$wpas_keys);
    $pageposts = $wpdb->get_results("SELECT * FROM $wpdb->posts WHERE (post_title LIKE '%$wpas_keys%') AND post_status = 'publish' ORDER BY post_date DESC");
    foreach ($pageposts as $post) {
        setup_postdata($post);
        echo "<rs id=\"";
        the_permalink();
        echo "\" info=\"" . autosuggest_excerpt(apply_filters('the_title', get_the_content())) . "\">";
        the_title();
        echo "</rs>";
    }
    echo '</results>';
    die();
}

define('AUTOSUGGEST_DIR', get_option('siteurl') . '/' . PLUGINDIR.'/'.dirname(plugin_basename(__FILE__)));


function add_autosuggest_css() {
    wp_register_style('autosuggestCSS', AUTOSUGGEST_DIR . '/css/wp_autosuggest.css', null, '1', 'screen');
    wp_enqueue_style('autosuggestCSS');
}

function add_autosuggest_js() {
    wp_register_script('autosuggestJS', AUTOSUGGEST_DIR . '/js/wp.autosuggest.js', null, '1');
    wp_enqueue_script('autosuggestJS');
}

function add_autosuggest_footer_code() {
?>
<script type="text/javascript">
var autosuggest_options = {
    script: "<?php echo AUTOSUGGEST_DIR; ?>/autosuggest.php?wpas_action=query&",
    varname: "wpas_keys",
    shownoresults:true,
    noresults:"<?php echo __('No results found.'); ?>",
    timeout:15000,
    callback:autosuggestSelected,
    maxresults: <?php echo get_wpas_option('wpas_maxresults','10'); ?>
};
var as = new AutoSuggest('<?php echo get_wpas_option('wpas_input_id','s'); ?>', autosuggest_options);
function autosuggestSelected(entry) {
    document.location = entry['id'];
}
</script>
<?php
}

function add_autosuggest_settings() {
?>
<div class="wrap">

    <?php

        $smsg = "";
        if (isset($_POST['submitoptions'])) {
            if (isset($_POST['wpas_input_id'])) {
                update_option('wpas_input_id',$_POST['wpas_input_id']);
            }
            if (isset($_POST['wpas_maxresults'])) {
                update_option('wpas_maxresults',$_POST['wpas_maxresults']);
            }
            ?>

            <div id="message" class="updated fade"><p>WP AutoSuggest settings updated.</p></div>

    <?php } ?>

    <h2>WP AutoSuggest Settings</h2>

    <form action="" method="post">
    <table class="form-table">
        <tr valign="top">
        <th scope="row">Search Input ID</th>
        <td>
        <input type="text" value="<?php echo get_wpas_option('wpas_input_id','s'); ?>" id="wpas_input_id" name="wpas_input_id"/><br/>
        Default value is 's' which is used with the default WordPress theme. 
        </td>
        </tr>
        <tr valign="top">
        <th scope="row">Max Results</th>
        <td>
        <input type="text" value="<?php echo get_wpas_option('wpas_maxresults','10'); ?>" id="wpas_maxresults" name="wpas_maxresults"/><br/>
        Maximum number of suggested results (10 by default).
        </td>
        </tr>
    </table>
    <p class="submit"><input type="submit" name="submitoptions" value="Update Settings" /></p>
    </form>
    </div>
<?php
}

function add_autosuggest_menu_settings() {
    if (function_exists('add_options_page')) {
         add_options_page(
             "WP AutoSuggest"
             , "WP AutoSuggest"
             , 7
             , basename(__FILE__)
             , 'add_autosuggest_settings');
    }
}

add_action('wp_print_scripts', 'add_autosuggest_js');
add_action('wp_print_styles', 'add_autosuggest_css');
add_action('wp_footer', 'add_autosuggest_footer_code');
add_action('admin_menu', 'add_autosuggest_menu_settings');


?>

相信大家没看几行就看出了问题的所在,变量wpas_keys是直接获取GET中的wpas_keys。一点都没过滤,并且在下面代码中,变量wpas_keys也带入数据库中查询了(wpdb是wordpress操作数据库方法),于是SQL注入就产生了。

四、参考链接

https://www.exploit-db.com/exploits/45977

https://www.freebuf.com/vuls/191869.html