After i knew how to secure upload image Bypassing forms input fields to upload unwanted files i would like to give another example of from with 2 filed, one of them are hidden.
SQL Table (id,name,jod,number)
CREATE TABLE `users` (
`id` bigint(20) unsigned NOT NULL auto_increment,
`name` varchar(255) default '0',
`job` varchar(255) default NULL,
`number` varchar(255) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
Form Code (support member will edit own informations)
<form action="send.php" method="post" name="send" id="send">
<input type="text" name="name" id="name" value="John"/>
<input type="text" name="job" id="job" value="Plumber"/>
<input type=hidden name="number" id="number" value="1234"/>
<input type="Submit" name="Submit" value="Submit"/>
</form>
Later there was an firefox extension that can bypassing different input to the server-side bypassing checking and might case a lot of damage so here it can stop the whole process and makes you able to edit the value of hidden table number to any such as value="1" causing update information for member have that value number 1.
That extension is working as following, It can fake input data before it passed to server side.
PHP Code Send.php
if(isset($_POST['send'])){
$name = mysql_real_escape_string($_POST[name]);
$job = mysql_real_escape_string($_POST[job]);
$number = mysql_real_escape_string($_POST[number]);
$sql= "update users SET name='$name',job='$job' WHERE number='$number'";
mysql_query($sql) or die("query failed: $sql".mysql_error());
echo "Update Done";
} else {
echo "Nothing to update";
}
The question
How then to protect this simple form from such input form ? ~ Thanks
this problems really hurts cause it made my website free to be hacked :)
If the user authorization is not an option in your cause, you could try the following techniques:
Set the hidden field with a hash of the number salted with some other information
Set the hidden field with the number encrypted (possible salt could increase security here also)
Of course it would add extra steps when sending the form HTML and validating the post information, but at least it would be much harder to the attacker fake a valid number on the post. Although it would not save you if the attacker knows the encrypted/hashed number of a different user unless the salted information withing the hidden field is used wisely.
You can't control what data people submit to your server.
You have to check, on the server, to see if the user is authorised to see the information or to make the change they are asking for.
For example:
able to edit the value of hidden table number to any such as value="1" causing update information for member have that value number 1.
The process would be something like:
Is anybody allowed to edit this field? If so, then OK.
Is the request coming from an authenticated user? If not, then return an error message and a login form
Is the request coming from the user with id=1? If so, then OK
If the request coming from a user who has admin permissions? If so, then OK
Return an error message.
If you have a form and any users to edit the values, this problem is going to be there. A better approach is to authenticate the users. Allow only the users who have logged in with an account to make the changes to their respective accounts.
Also, don't use mysql_query or anything like mysql_*, they are insecure and depreciated in php5.
A hidden field cannot be secured. It's 100% impossible to prevent malicious people from editing it.
The best you can possibly do is validate its data.
For the example field, the best you can do is make sure it's actually a number.
But that doesn't help any.
What you need to do is have the OLD data sent as hidden data. ALL of it. Complete with the old id.
Then you validate both the old and new data. Make sure there's no injected sql code in them. Having done this you would have
$name
$job
$id
$old_name
$old_job
all set. Then you can.
select * from users where name="$old_name" and job="$old_job
if you get back a row, then you can
update users set name="$name", job="$job$" where id=$id
Now, even if the user changes the ID, it won't do a thing, because the select will return 0 rows, ad the edit attempt will abort.
Now if someone happens to know all three fields for someone else's entry, they can still change it. The only way around that is force authentication, and have another database tying username/password pairs to IDs.
Related
I have few checkboxes in my template whos value is the id of database row. I am using AJAX to post these values back and forth.
{% for item in sale_order_items %}
<tr>
<td class="text-center">
<input type="checkbox" name="saleorderitem" value="{{item.id}}">
</td>
</tr>
item.id for instance renders to 1. Now what if the user changes the value from 1 to 2 in browser using "inspect" and submits the form. what can I do at the frontend or django backend to prevent this and check if the user is submitting the same values as intended?
This depends on many different things but to take you back to the basics: When you create a function in order to bulletproof it out of any errors you use type and value checks.
I would think the best approach to this is to add some back-end checks. The form values returned would have to adhere a set of rule such as a value threshold. If the value returned is beyond that threshold then that would mean that something has changed in the HTML.
You add a check if it fails then the back-end would return an error. In collaboration with front-end you refresh the page and return an error message. It might be really terrible UX but an average end user would never change values using their inspector.
The other alternative is to use javascript to detect any kind of HTML/DOM mutations or changes which I would advice against. Having values to be checked against specific criteria (using the back-end) is best as it foolproofs info passed on to your server against any change.
I found a solution, in this scenario django session variable can be used to store data between requests. When I load the form, I set the session variable to the required values, then on form submission, I check the submitted values with the values in session variable. And it works.
At the moment i have htp.print and DBMS_output to show the me the end result of user input. however, htp.print shows the confirmed message on the web browser and my DBMS_output doesn't work for some reason. But what i'm looking for is the confirmation message which will pop up and show to the user. i have tried java script and for some reason that is not working either. below are the syntax.
-- button and input text field
HTP.FORMOPEN ('BANINST1.UAP.P_UNSUSPEND_SEARCH', 'post');
HTP.P ('<input type="text" method="post" name="bannerid" id="bannerid" placeholder="e.g. 000123456" maxlength="9"
autocomplete="off" required>');
HTP.FORMSUBMIT ('', 'Submit', cattributes => 'onclick="confirmMsg()"');
HTP.FORMCLOSE;
-- javascript confirmation message which is not working
htp.p ('<script type="text/javascript">
function confirmMsg() {
var field1 = document.getElementById("bannerid").value;
alert(field1+" has been unsuspended");
}
</script>');
Assuming you are looking for ways to generate log messages from the DB Backend, I see basically 2 ways to achieve this:
(1) Persist your messages to a table inside an autonomous transaction. A complete example can be found here.
(2) If you have access to the DB servers file system, you can also write messages to text files using the UTIL_FILE package.
I am working on a small app using phalcon for php framework. I have implemented multiple controllers and models, but so far when I want to edit a user for example, i use a link that links to
localhost/myappname/User/edit/11 "user's id"
I was told this is not the best way to do this, and I am trying to do this without passing the id through the url, like using post method like in forms but without success so far.
Is this the only correct way to edit or delete an entry or it there something better?
I tried to search for the problem but couldn't figure how to name this question so I am yet to find an answered question.
If you don't want to let everyone access to edit page you can do this in a few ways.
Solution #1
You can use Phalcon ACL to block user's who has no permission to edit this page so only allowed people like managers can edit user or whatever.
See Access Control Lists ACL
Solution #2
You can crypt/decrypt user id so in URL it will not be readable by humans and then in edit method try to dectypt that id and if it is not a valid echo error.
<?php
use Phalcon\Crypt;
// Create an instance
$crypt = new Crypt();
$key = 'le password';
$user_id = 5;
$encrypt = $crypt->encryptBase64($user_id, $key);
// Use $encrypt for URL like Edit
// Use decrypt to get the real id of a user
$crypt->decryptBase64($encrypt, $key);
?>
In this way users will see URL something like
localhost/myappname/User/edit/nomGPPXd+gAEazAP8ERF2umTrfl9GhDw1lxVvf39sGKF34AFNzok31VdaT/OwADPPJ4XgaUNClQKrlc/2MfaXQ==
For more info see Encryption/Decryption
But my personal opinion is that it is better to go with ACL. After all ACL was made for that kind of things.
Note! If you want to use Encrypt/Decript remember to wrap decryption
in edit method in try/catch block and catch exception so you don't
get Error if someone tries to guess sone id.
Solution #3
If you still want to do that using POST then don't use Edit instead you can try something like:
<form method="POST">
<input type="hidden" name="uid" value="{{ user_id }}"/>
<button type="submit">Edit</button>
</form>
And then in edit method catch that id like:
<?php
$user_id = $this->request->getPost("uid");
?>
NOTE! In this way your URL will not contain user id but someone still
can POST another uid so you can try to hide that real user id even
from input type hidden. You can use again crypt/decrypt so input
hidden uid can be crypted and then decrypt post data in method.
you could use sessionStorage. It would store the value of the userId in the browser and be deleted as soon as they leave the page.
http://www.w3schools.com/html/html5_webstorage.asp
set on one page
sessionStorage.userId = 11;
access on another
var user = sessionStoarge.userId;
I am trying to develop a profile form in Joomla so users can update their information - including changing their password.
However, as can be seen in the below example, the dots just flow beyond the viewable string in the field. Is there a way I can show the correct number of dots for the users password? For example, a user with an 8 character password:
<form>
<input type="password" name="psw" value="********">
</form>
<form>
<input type="password" name="psw" placeholder="********">
</form>
I'm getting the input field populated as this:
PS I'm aware aware of identifying password length as in this question. However, with hashing/salting for the type of site this is that it is acceptable
Updated slightly to incorporate the comments.
In the first example (with "value") what you are doing is setting the actual value of the password to a series of '*' if the form is saved. Then the Joomla password field is doing what it does which is to obfuscate the new password.
I don't know if you can use a place holder give that the field has a value (although the value is not displayed). If it would the placeholder would be something like "Enter new password". The password will be automatically obfuscated as the user types it. However if a password already exists neither a placeholder nor a value would be rendered by the field.
From what I can tell you are talking about editing the profile, in which case there is an existing password.
The Joomla password field never displays back the original password once it has been set, it just provides a blank space for the user to change passwords if desired. If a user is changing their password they should just see an empty field and then one dot for each character they type. The password field cannot show the existing password because it is hashed in the database. There is no way for the field to retrieve the actual password, only the hashed password. The only way to get the real password is for the user to type it in.
You don't say where $pass is coming from but if you are pulling it from the database it is the hashed value and then it is going to be double hashed on save.
Is there really a good reason not to use the Joomla profile edit form? Or if there is not to just copy and modify it?
So as the title says I'm curious, can user change the ID of an element through browser? I have a list of inputs - checkboxes, when you click on one of them ajax takes ID of that element and uses it to get data from database, so basically what I'm thinking is that if it is somehow possible to change the ID of the element my database wouldn't be secured. If that's possible, how I should protect it?
Okay, So I get the idea that it wouldn't be secured, If I'd use this way:
<?php
$mysqli = new mysqli("host", "user", "password", "database");
$usuario = $mysqli->real_escape_string($_POST["usuario"]);
$clave = $mysqli->real_escape_string($_POST["clave"]);
$sql=' SELECT * FROM usuarios
WHERE username="'.$usuario.'"
AND pass="'.$clave.'"
';
$mysqli->query($sql);
$mysqli->close();
?>
would it be enough, or there aren't actually safe enough way to protect data?
You are correct that this would be a security hole. The ID attributes could indeed be changed via the browser console.
Yes, they can change it or just make while request faked and you won't tell the difference. Rule of thumb here is NEVER trust any data that comes from user. It means - always validate, sanitize data on server-side, and always assume data that comes in request are there to fool/trick/hack you.
Yes. The user can do anything they like to the DOM once it is in their browser.
They can also execute any JS they like there.
You're worrying about the problem in the wrong place though. Your control ends at the edge of the webserver. Clients can make any HTTP request they like to it and include any id value they want. You need to address security there and not in the browser.
If you want to secure your database then you need to either allow no HTTP request to lead to the secret data being released / changed or you need to write server side rules that limit which HTTP requests can change them.
Typically this would involve Knowing Who The Request Comes From (Authentication) and Knowing Who Can Access Which IDs (Authorization).
A simple approach would be to keep a database that has a users table (including hashed passwords), a "things" table, and an ownership table (which has a column of user ids and a column of thing ids). If the request doesn't include a username and password you can cross reference from the thing id across the ownership table - return an error message instead of what was asked for.