Skip to main content

How to prevent mysql sleep injections?


Recently, we faced an issue with website which was developed around one year back. One hacker successfully tried to slow the website using sleep injection. Although we were using precautions like mysqli_real_escape_string() for escaping SQL string syntax correctly. Let’s see why this happened then and what are the solutions?

We were using following code to get product id passed through query string.

$id   = mysqli_real_escape_string($con , (isset($_REQUEST['id']) ? $_REQUEST['id'] : 0));
$qry = "Select * from products where id = ".$id;

but hacker tried to change the the query string as : 

?id=3 and sleep(4)

and query becomes

Select * from products where id = 3 and sleep(4);

And it started taking around 4+seconds to run the query. So in this way website become too slow.

We were trying to figure out the possible and the best solution.

After spending some time we noticed that although we were using mysqli_real_escape_string() function but we were not using it properly. Everytime we use mysqli_real_escap_string(), the returned string must be used with single quotes although it’s numeric or string. So quick solution for that problem was to change the query as :

$id   = mysqli_real_escape_string($con , (isset($_REQUEST['id']) ? $_REQUEST['id'] : 0));
$qry = "Select * from products where id = ‘".$id."";

It is a quick solution but not the best one.

We could have also checked if the input is numeric or not.

Note : For future reference I would like to say please don’t use mysql_ extensions anymore. mysql_ extension is deprecated as of PHP 5.5, and will be removed in future.

Use mysqli or PDO prepared statements. Best is PDO statements.

The internet (and many respectable CS courses) are littered with examples using mysql_query() and string concatenation, half of which train people to create SQLI bugs or don't explain why escaping is needed; it's too late to undo the damage already done but at least people new to PHP will hopefully be told now that there is a better way. Although we can’t say PDO is 100% not vulnerable to errors but we don’t need to use external functions to cover sql injections. So as a programmer I would suggest and request to all the developers community to use PDOs in future reference.

Reference :


Thanks!!!!!!!!!!!!!! Enjoy Programming :)


Comments

Popular posts from this blog

Odoo: Qweb Templates Cache Issue

Hi Everyone, Today I was working on a hotel booking template in Odoo and changes made in the Qweb template(.xml) were not reflecting on updating module with odoo service restart. Tried few times without any success :(. Finally, I decided to delete the old template from Odoo backend and then update module again and it worked like a charm!! :) Steps to delete template from backend: Settings --> User Interface --> Views --> Search by template name Delete the used template. Although it's a small post, but I'm sure it will meet the purpose and help someone in the future. Thanks!!! Enjoy Programming!! :) Reference Links: =================================== https://www.odoo.com/forum/help-1/question/odoo-cache-and-updating-qweb-templates-84492

Odoo12/13: Add an extra action in the tree view action button

This post will help you to add an action window in Odoo. Odoo13: <act_window id="action_make_bank_payment"              name="Do Bank Payment"              res_model="account.ob.payment"              binding_model="account.move"              view_mode="form"              target="new"              binding_views="list,form"              domain="[('type','=', 'in_invoice')]"              groups="account.group_account_user" /> Odoo12: <act_window id="action_make_bank_payment"              name="Do Bank Payment"              res_model="account.ob.payment"             view_mode="tree,form"              domain="[('type','=', 'in_invoice')]"              groups="account.group_account_user" /> Thanks!!! Enjoy Programming!! :) Reference: https://www.odoo.com/es_

Odoo/OpenERP: one2one relational field example

one2one relational field is deprecated in OpenERP version>5 but you can achieve the same using many2one relational field. You can achieve it in following two ways : 1) using many2one field in both the objects ( http://tutorialopenerp.wordpress.com/2014/04/23/one2one/ ) 2)  using inheritance by deligation You can easily find the first solution with little search over internet so let's start with 2nd solution. Scenario :  I want to create a one2one relation between two objects of openerp hr.employee and hr.employee.medical.details What I should do  i. Add _inherits section in hr_employee class ii. Add field medical_detail_id in hr_employee class class hr_employee(osv.osv):     _name = 'hr.employee'     _inherits = {' hr.employee.medical.details ': "medical_detail_id"}     _inherit = 'hr.employee'         _columns = {              'emp_code':fields.char('Employee Code', si