What are php input attack,and how to protect from input attack
i allow user to enter data from 11 input field
i need to know php attacks and how can i protect from attack can someone give me idea about php attack's
a how can i protect from user input do i need to create php function are and validate function using jquery
can someone give me idea attacks and prevention
user input are saved to sql after processing
PHP-specific bugs aren't really a huge issue. What you should worry about are generic input-poisoning attacks.
These include:
SQL Injection
XSS
Shell script escaping
There are probably others that I've forgotten, but that's where you should start. I would also advise asking more specific questions. Asking simply about security in PHP is much too broad of a subject.
A good resource for PHP security however would be OWASP
Related
I am just reading up about mysql injection and I wanted to confirm that if you force a user to use list options for their input that is written to mysql (and those inputs are set as readonly) is the system essentially secure from mysql injection? would one need to put in measures to protect malicious mysql injection attempts for sites developed this way?
If I understand you correct then no.
You can try to force the user but everything that the user enters, happens on the client side. Since this is on the clients side and the client has absolute control over the webpage he can manipulate it to whatever he wants or even genereate own POST or GET Requests regardless of the page he received.
There are some tools that can achieve this goal.
If you want to secure your database against SQL Injection I recommend that you use prepared statements only (How can I prevent SQL injection in PHP?)
Any countermeasures that you take have to be implemented on the server side. You should always expect that the user sends whatever will break your code and do harm to you, regardless of the "restrictions" he has to his input.
Based on the information provided in the question:
Q: ... is the system essentially secure from mysql injection?
A: No, this doesn't guarantee that the system won't be vulnerable to SQL Injection.
Q: would one need to put in measures to protect malicious mysql injection attempts for sites developed this way?
A: The best measures against a malicious attacker exploiting a SQL Injection vulnerability is to prevent SQL Injection vulnerabilities in the first place.
And that means speicific coding patterns for the database interactions: prepared statements with bind placeholders. Or, at a minimum, properly escaping all potentially unsafe values that are included in the text of a SQL statement.
Your web page can have a drop down list box from which the user makes a choice, and your web page can do validation in Javascript. But that doesn't prevent a malicious attacker from bypassing that, and sending a request that doesn't conform the javascript validation.
The script on the server that handles the request will need to perform the validation... probably the same validation that was done in javascript on the web page that generated the request.
But any database interactions will also need to follow the normal patterns that prevent SQL Injection vulnerabilities (i.e. prepared statements with bind placeholders, or at a minimum, properly escaping potentially unsafe values.)
Multiple lines of defense.
It's not at all clear what you've been reading.
As a starting point, I recommend you review the information available from the OWASP project.
https://www.owasp.org/index.php/SQL_Injection
This isn't the be-all-end-all, but it's a good overview. If you are in a hurry, you can look at the SQL Injection Prevention Cheat Sheet.
i read it some where in form that xss clean in codeigniter dosn't not prevent in sql injection and it should not be used in input but it should be used in output it is true... Please can any one explain.. then how to prevent from sql injection in codeigniter.
Thank you for replaying me..
and sorry for the bad english..
First of all, both topics are not specific to CodeIgniter.
But CodeIgniter has specific way to handle some of this. Please read https://ellislab.com/codeigniter/user-guide/general/security.html
Remember that CodeIgniter will not save you from any of these and you must understand how both of these attacks works.
It is important to understand these are two different attacks, as with any attacks, they could be coupled together. For example using a XSS/CSRF to perform a SQL injection via. a crafted link to a administrator or etc.
XSS is when the attacker can inject code to be executed on the clientside. For example placing a <script> tag in your code. This often happens if you output data which the user has provided without sanitizing it or validating it. Typically this could be their username, a post title, $_GET data and etc. There are alot more ways to get a script executed on the clientside other than a script tag, so make sure to read up on the subject.
To avoid it, always escape user inputted data, from any source.
You can read more about it https://www.owasp.org/index.php/Cross-site_Scripting_%28XSS%29
SQL injection is when the attacker can change the SQL query for a malicious purpose. The most common way to avoid injection is to make sure to escape every input, before passing it to a query. Using prepared statement also helps alot. In CodeIgniter, you often use the "ActiveRecord" db thing, which escapes the input for you.
You can read more about it, including examples https://www.owasp.org/index.php/SQL_Injection
You should also read https://www.owasp.org/index.php/Top_10_2013-Top_10 and become familiar with the most common attacks.
In class we're now learning about SQL injection attacks and my professor showed us examples where we either use only the username input for the attack, or both the username and password.
I started reading about SQL injection more and found that you can create attacks by typing 'admin' or 'xx' into the username input and then primarily using the password input for the attack.
My question is, is it possible to perform a SQL injection attack using only the password input and typing nothing in the username input?
EDIT: This question is in the context of using a SQL injection attack on a database via the password box of a login page of a website.
is it possible to perform a SQL injection attack using only the password input and typing nothing in the username input?
Yes.
If you're asking this, then your professor failed with explanation. He's not alone, though.
Most people in the world do confuse the injection and the exploit. Taking one for the another.
What your professor demonstrated to you was exploit. Yes, various particular exploits involve various particular query parts. But the principle of injection is breaking of the query integrity. That's all. As long as you can inject any code into query, it is vulnerable. Will you be able to exploit it or not - that's another matter, one have to learn SQL, not injections for this.
But the point of injection is just breaking of query integrity. And for this matter it doesn't matter, be it password or "remember me" checkbox. Comprehensible?
For the better understanding I'll recommend you an article, I wrote aiming protection from injections, but it surely can help you to understand the injection too. The first three chapters and appendices could be of the most help. Here it goes: The Hitchhiker's Guide to SQL Injection protection
Yes it's possible depends on how code is written to validate . If code is written only to get a true/false result set. You can very much anything to get a true result and get into application . For example select '1' from xyz where username='xxx' or yy=yy
For example, let's say I have a website that receives and displays user comments (text). I am concerned with vulnerabilities from receiving user submissions and also when the submissions are displayed.
Concerns:
Cross-site scripting attack
SQL injection
My question is are there more attacks that could come from user text inputs? Also, in what ways can I guard against such attacks using PHP, Javascript?
Thanks, and merry Xmas!
JavaScript is not a barrier from XSS, CSRF attacks, so you should care about server side protection. If you talk about functions then these will help you from XSS: htmlentities(), strip_tags(), utf8_decode(); and as Zar said mysql_real_escape_string will help you from SQL injection.
There are a lot of articles devoted to SQL injections, XSS, CSRF, sessions hijacking. Go to http://phpsec.org/projects/guide/ and read it all.
You can use strip_tags($var) to guard yourself against XSS.
mysql_real_escape_string($var) will give you basic SQL injection protection.
Have a look at php Filter Library, which made to clean and validate different types of data, from boolean to email addresses, functions like filter_input and filter_input_array could make your application more secure and smart.
If you are using ajax to send some form data to the server as part of url, encode them like this
encodeURIComponent(yourFormInputData);
and remember to decode them on the server side.
I'm doing this simple tutorial on the following website:
http://www.phpeasystep.com/phptu/6.html
Is the code that they use safe or could a hacker possibly enter somehow?
Thanks
PS: If there are problems, what are they, how can I prevent them. Is there maybe an even better tutorial?
That script protects against SQL Injection attacks but could possibly be vulnerable to an XSS (Cross Site Scripting) attack. You should add enforcement of allowed characters on at least the username to keep out anything but alphanumeric and a limited set of punctuation. For ease of use on your users, you should do this check in javascript to make the site more responsive but you must do it in the PHP code to be truly protected against XSS.