I am trying to find a way to filter ajax calls in order to add a fine layer of security to my applications. Does the code bellow make any sense?
function is_ajax(){//Help Secure Ajax Calls
if(isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH']=='XMLHttpRequest') return;
else die;//no ajax
}
My dream is only let a file inside my server (htm or php) to access another php file via ajax.
I wonder if the code bellow would not do better:
if(strpos($_SERVER['REQUEST_URI'],'http://')) die;//Help Secure From URL Include Attacks
Thanks.
Since the AJAX call is always made from the browser, the request is not coming from your own server, but the client machine. Even if you set custom headers, these can easily be manipulated on the client side.
If your goal is to only allow your own scripts to access the script containing the ajax content, I'd recommend generating a token string that is only valid for a certain requested url and a specified time.
Quick and dirty example:
Script requesting the AJAX resource:
$secret ="ABC1232";
$item = array(
"time"=>time(),
"token_id"=>"<page_url>"
);
$signed = base64_encode(hash_hmac("sha256",json_encode($item),$secret));
$item = base64_encode(json_encode($item));
$ajax_url = "myscript.php?signed=$signed&item=$item";
AJAX Resource, check the token is valid
$item = json_decode(base64_decode($_REQUEST["item"]));
$timeout = 3600;
if($item->time < (time()-$timeout)){
die("Invalid token - timeout");
}
if($item->token_id !== "<page_url>"){
die("Invalid token - page url");
}
$secret ="ABC1232";
$valid = ($_REQUEST["signed"] === base64_encode(hash_hmac("sha256",json_encode($item),$secret));
if(!$valid){
die("Invalid token");
}
Your Ajax is as secure as your application layer. Ajax is just client side code accessing server side code. There is probably no way in securing it the way you want since anyone can emulate Ajax calls from within any language by just modifying the request headers. One more thing most ajaxified frameworks do include HTTP_X_REQUESTED_WITH but it's not 100% reliable.
Just secure your server code and your good to go. If you really want to at least let your server code know that it's receiving an ajax call, use a parameter on the request.
Assume that anything that can be requested by AJAX will also be accessed directly and you will be in a much safer place. You really should consider why you would only ever want something to be accessed via AJAX in the first place. The HTTP_X_REQUESTED_WITH header is unreliable and easily spoofed so it provides no real security anyway.
I think for a little more security you could decode your secret string after you encode it. then echo than decoded string in php and then copy it.
then on the the $valid variable
$valid = (base64_decode($_REQUEST["signed"]) === "blahblahblah that you copied from php");
Related
Im looking for an elegant way to hand over data/params when using $f3->reroute();
I have multiple routes configured in a routes.ini:
GET #sso: /sso/first [sync] = Controller\Ccp\Sso->first, 0
GET #map: /map [sync] = Controller\MapController->second, 3600
Now I reroute(); to #map route, from first();
class Sso {
public function first($f3){
$msg = 'My message!';
if( !empty($msg) ){
$f3->reroute('#map');
}
}
}
Is there any "elegant" way to pass data (e.g. $msg) right into $MapController->second(); ?
I don´t want to use $SESSION or the global $f->set('msg', $msg); for this.
This isn't an issue specific to fat-free-framework, but web in general. When you reroute, you tell the browser to redirect the user's browser page using a 303 header redirect code.
Take a minute to read the doc regarding re-routing: http://fatfreeframework.com/routing-engine#rerouting
There seems to be some contradicting information in your question, which leads me to question the purpose of what you are trying to achieve.
If you are rerouting, you can either use the session, cookies, or use part of the url to pass messages or references to a message.
If you do not need to redirect, but just want to call the function without changing the passed parameters, you could abstract the content of the function and call that function from both routes. You could also use the $f3 globals, which are a great way of passing data between functions in cases where you don't want to pass the data using the function call. is there a reason why you don't want to to use this? The data is global for the single session, so there is no security concern, and the data gets wiped at the end of the request, so there is very little extra footprint or effect on the server.
If you're alright with not using #map_name in re-routes you can do something like this:
$f3->reroute('path/?foo=bar');
Not the prettiest I'll admit. I wish $f3->reroute('#path_name?foo=bar') would work.
Introduction
I've read the following:
Hypertext Transfer Protocol (HTTP) is the life of the web. It's used every time you transfer a document, or make an AJAX request. But HTTP is surprisingly a relative unknown among some web developers.
The HTTP verbs comprise a major portion of our “uniform interface” constraint and provide us the action counterpart to the noun-based resource. The primary or most-commonly-used HTTP verbs (or methods, as they are properly called) are POST, GET, PUT, and DELETE.
Huh?
Well, we came to the point I lost track of things.
PUT and DELETE, they say. I've only ever heard of POST and GET and never saw something like $_PUT or $_DELETE passing by in any PHP code I've ever viewed.
My question
What are these methods (PUT) and (DELETE) for and if it's possible to use them in PHP, how would I go about this.
Note: I know this is not really a problem but I always grab a learning opportunity if I see one and would very much like to learn to use these methods in PHP if this is possible.
What are these methods (PUT) and (DELETE) for...
There are a lot of words to spend to explain this, and I'm not skilled enough to do it, but as already posted, a quick recap of what the HTTP specification describes.
The protocol basically says this:
use GET when you need to access a resource and retrieve data, and you don't have to modify or alter the state of this data.
use POST when you need to send some data to the server. Ex. from a form to save these data somewhere.
use HEAD when you need to access a resource and retrieve just the Headers from the response, without any resource data.
use PUT when you need to replace the state of some data already existing on that system.
use DELETE when you need to delete a resource (relative to the URI you've sent) on that system.
use OPTIONS when you need to get the communication options from a resource, so for checking allowed methods for that resource. Ex. we use it for CORS request and permissions rules.
You can read about the remaining two methods on that document, sorry I've never used it.
Basically a protocol is a set of rules you should use from your application to adhere to it.
... and if it's possible to
use them in PHP, how would I go about this.
From your php application you can retrieve which method was used by looking into the super global array $_SERVER and check the value of the field REQUEST_METHOD.
So from your php application you're now able to recognize if this is a DELETE or a PUT request, ex. $_SERVER['REQUEST_METHOD'] === 'DELETE' or $_SERVER['REQUEST_METHOD'] === 'PUT'.
* Please be also aware that some applications dealing with browsers that don't support PUT or DELETE methods use the following trick, a hidden field from the html form with the verb specified in its value attribute, ex.:
<input name="_method" type="hidden" value="delete" />
Follow an example with a small description on a possible way to handle those 2 http requests
When you (your browser, your client) request a resource to an HTTP server you must use one of the method that the protocol (HTTP) accepts. So your request needs to pass:
A METHOD
An Uri of the resource
Request Headers, like User-Agent, Host, Content-Length, etc
(Optional body of the request)
Now, while you would be able to get data from POST and GET requests with the respective globals ($_GET, $_POST), in case of PUT and DELETE requests PHP doesn't provide these fast access globals; But you can use the value of $_SERVER['REQUEST_METHOD'] to check the method in the request and handle your logic consequently.
So a PUT request would look like:
PUT /something/index.php
(body) maybe=aparameter
and you can access those data in PHP by reading the php://input stream, ex. with something like:
if ($_SERVER['REQUEST_METHOD'] === 'PUT') {
$myEntireBody = file_get_contents('php://input'); //Be aware that the stream can only be read once
}
and a DELETE request would look like:
DELETE /something/index.php?maybe=aparameter
and again you can build your logic after have checked the method:
if ($_SERVER['REQUEST_METHOD'] === 'DELETE') {
// do something
}
Please pay attention that a DELETE request has no Body and pay very attention to Response Status Code too (ex. if you received a PUT request and you've updated that resource without error you should return a 204 status -No content-).
Way to use PUT data from PHP:
$method = $_SERVER['REQUEST_METHOD'];
if ('PUT' === $method) {
parse_str(file_get_contents('php://input'), $_PUT);
var_dump($_PUT); //$_PUT contains put fields
}
PHP's $_GET and $_POST are poorly named. $_GET is used to access the values of query string parameters, and $_POST lets you access the request body.
Using query string parameters is not limited to GET requests, and other kinds of requests than just POST can come with a request body.
If you want to find out the verb used to request the page, use $_SERVER['REQUEST_METHOD'].
Most suitable place to use these (PUT and DELETE) methods is REST API. Where we use http methods to define the mode of operation for example you want to fetch any resources then you can use following:
GET http://api.example.com/employee/<any_id>
to add a new item:
POST http://api.example.com/employee/
to Update or Edit:
PUT http://api.example.com/employee/
to Delete an existing resource:
DELETE http://api.example.com/employee/1
etc.
Now on PHP side you just need to read what HTTP method used so that you can make an action according to that.
There are lots of libraries available which can do that for you.
What are these methods (PUT) and (DELETE)
There are described in the HTTP spec.
In a nutshell, and simplifying somewhat, PUT is for uploading a file to a URL and DELETE is for deleting a file from a URL.
never sawy something like $_PUT or $_DELETE passing by in any PHP code I've ever viewed
$_POST and $_GET are terribly named superglobals. $_POST is for data parsed from the request body. $_GET is for data parsed from the URL. There's nothing that strictly ties data in either of those places (especially the URL) to a particular request method.
DELETE requests only care about the URL's path, so there is no data to parse.
PUT requests usually care about the entire request body (not a parsed version of it) which you would access with file_get_contents('php://input');.
for and if it's possible to use them in PHP, how would I go about this.
You'd need to map the URL onto a PHP script (e.g. with URL rewriting), test the request method, work out what URL you were actually dealing with, and then write code to do the appropriate action.
$GLOBALS["_PUT"]=null;
if($_SERVER['REQUEST_METHOD'] == 'PUT') {
$form_data= json_encode(file_get_contents("php://input"));
$key_size=52;
$key=substr($form_data, 1, $key_size);
$acc_params=explode($key,$form_data);
array_shift($acc_params);
array_pop($acc_params);
foreach ($acc_params as $item){
$start_key=' name=\"';
$end_key='\"\r\n\r\n';
$start_key_pos=strpos($item,$start_key)+strlen($start_key);
$end_key_pos=strpos($item,$end_key);
$key=substr($item, $start_key_pos, ($end_key_pos-$start_key_pos));
$end_value='\r\n';
$value=substr($item, $end_key_pos+strlen($end_key), -strlen($end_value));
$_PUT[$key]=$value;
}
$GLOBALS["_PUT"]=$_PUT;
}
if (!function_exists("getParameter")){
function getParameter($parameter)
{
$value=null;
if(($_SERVER['REQUEST_METHOD'] == 'POST')&& (isset($_POST[$parameter]))){
$value=$_POST[$parameter];
}
else if(($_SERVER['REQUEST_METHOD'] == 'PUT')&& (isset($GLOBALS["_PUT"][$parameter])))
{
$value=$GLOBALS["_PUT"][$parameter];
}
else if(($_SERVER['REQUEST_METHOD'] == 'DELETE')&& (isset($_DELETE[$parameter]))){
$value=$_DELETE[$parameter];
}
else if(($_SERVER['REQUEST_METHOD'] == 'PATCH')&& (isset($_PATCH[$parameter]))){
$value=$_PATCH[$parameter];
}
else if(isset($_GET[$parameter])){
$value=$_GET[$parameter];
}
return $value;
}
}
The actual questions
How to "map" access restrictions so it can be used from php and javasript?
What kind of method should I use to share access restrictions / rules between php and javascript?
Explanation
I have created a RESTful backend using php which will use context-aware access control to limit data access and modification. For example, person can modify address information that belongs to him and can view (but not modify) address information of all other persons who are in the same groups. And of course, group admin can modify address details of all the persons in that group.
Now, php side is quite "simple" as that is all just a bunch of checks. Javascript side is also quite "simple" as that as well is just a bunch of checks. The real issue here is how to make those checks come from the same place?
Javascript uses checks to show/hide edit/save buttons.
PHP uses checks to make the actual changes.
and yes,
I know this would be much more simpler situation if I ran javascript (NodeJS or the like) on server, but the backend has already been made and changing ways at this point would cause major setbacks.
Maybe someone has already deviced a method to model access checks in "passive" way, then just use some sort of "compiler" to run the actual checks?
Edit:
Im case it helps to mention, the front-end (js) part is built with AngularJS...
Edit2
This is some pseudo-code to clarify what I think I am searching for, but am not at all certain that this is possible in large scale. On the plus side, all access restrictions would be in single place and easy to amend if needed. On the darkside, I would have to write AccessCheck and canAct functions in both languages, or come up with a way to JIT compile some pseudo code to javascript and php :)
AccessRestrictions = {
Address: {
View: [
OWNER, MEMBER_OF_OWNER_PRIMARY_GROUP
],
Edit: [
OWNER, ADMIN_OF_OWNER_PRIMARY_GROUP
]
}
}
AccessCheck = {
OWNER: function(Owner) {
return Session.Person.Id == Owner.Id;
},
MEMBER_OF_OWNER_PRIMARY_GROUP: function(Owner) {
return Session.Person.inGroup(Owner.PrimaryGroup)
}
}
canAct('Owner', 'Address', 'View') {
var result;
AccessRestrictions.Address.View.map(function(role) {
return AccessCheck[role](Owner);
});
}
First things first.
You can't "run JavaScript on the server" because Javascript is always run on the client, at the same way PHP is always run on the server and never on the client.
Next, here's my idea.
Define a small library of functions you need to perform the checks. This can be as simple as a single function that returns a boolean or whatever format for your permissions. Make sure that the returned value is meaningful for both PHP and Javascript (this means, return JSON strings more often than not)
In your main PHP scripts, include the library when you need to check permissions and use the function(s) you defined to determine if the user is allowed.
Your front-end is the one that requires the most updates: when you need to determine user's permission, fire an AJAX request to your server (you may need to write a new script similar to #2 to handle AJAX requests if your current script isn't flexible enough) which will simply reuse your permissions library. Since the return values are in a format that's easily readable to JavaScript, when you get the response you'll be able to check what to show to the user
There are some solutions to this problem. I assume you store session variables, like the name of the authorized user in the PHP's session. Let's assume all you need to share is the $authenticated_user variable. I assume i'ts just a string, but it can also be an array with permissions etc.
If the $authenticated_user is known before loading the AngularJS app you may prepare a small PHP file whish mimics a JS file like this:
config.js.php:
<?php
session_start();
$authenticated_user = $_SESSION['authenticated_user'];
echo "var authenticated_user = '$authenticated_user';";
?>
If you include it in the header of your application it will tell you who is logged in on the server side. The client side will just see this JS code:
var authenticated_user = 'johndoe';
You may also load this file with ajax, or even better JSONP if you wrap it in a function:
<?php
session_start();
$authenticated_user = $_SESSION['authenticated_user'];
echo <<<EOD;
function set_authenticated_user() {
window.authenticated_user = '$authenticated_user';
}
EOD;
?>
I'm building an application that's self-hosted, and I'd like to have some form of licensing to minimize fraudulent downloads/distribution.
Of course, I'm well aware that being self-hosted someone could simply rip out all license features from the source-code, but the con's of using a compiler like Zend Guard or ionCube far outweigh the pro's in my opinion - nonetheless I'd like to have some basic form of license security.
What I originally had in mind to do was: user logs in with license on app -> app posts license to my server -> server sends a response via a HTTP GET request -> app evaluates response, and if license is valid sets a value in a session variable (A), if invalid returns to login screen with an error.
The problem with this is, the evaluation of response/session setting is readily available in a application file, so if the user knows a little PHP and checks in on that source code, they'll realize all they'll need to do is set a session themselves with a particular $_SESSION['_valid_license'] value, and they'll be good to go.
What I was considering doing to make it a little less easy was (if possible) to post PHP back as a response, and then have the application file execute it, for example:
My original code:
$response = $_GET['response'];
if($response == "fjdkuf9") {
start_session();
$_SESSION['_valid_license'] = "YES";
header("Location:" . $rp . "/admin/");
} else {
header("Location:" . $rp . "/login/?err=1");
}
My new concept:
$response = $_POST['response'];
str_replace("\", "", $response);
With the following being posted as response:
start_session();
\$_SESSION[\'_valid_license\'] = \"YES\";
header(\"Location:\" . \$rp . \"/admin/\");
Would that execute $response as actual PHP code after str_replace()? If possible, this would be great, as it would mean evaluation would be done on my server rather than within the self-hosted app itself.
Your second solution is just as insecure as the first. here's what I would do:
Your application POSTS to your server a serial number or some other identifying information.
Your server validates the serial number against the user's account or whatever and returns a unique response.
If that response is successful, you allow the user to continue. Obviously you'd want to implement some sort of caching mechanism here so you're not having to hit you server on every page view.
Putting the responsibility of validation on your server instead of self-hosted code is much more secure. You would need to encrypt the data that is sent BTW so that someone couldn't simply emulate the success response, but you get the idea.
How would I go about writing a simple PHP bot that could login in and recieve all the cookies sent by the server? ... and then send them back when required?
Any suggestions would be appreciated.
First of all, your question is too broad and lacking in detail to really answer effectively. That said, I'll give it a try.
Not knowing what exactly you mean by "log in", I assume you want the script to be able to post some data to another script via an HTTP request. The CURL Library is good for that. It is able to post data and handle cookies.
Edit: Got ninja'd by Zed. ;)
If for some reason you cannot use the curl extension on your server (extension not installed), you can use a class such as Snoopy which will still allow you to either use the curl binaries or use sockets to retrieve the information.
Snoopy handles cookies.
As for the writing the bot itself, it's just a question of sending the proper requests. Here is an example with Snoopy:
$snoopy = new Snoopy;
// The following needs to reflect the form configuration of the site
$login = array('usr' => 'hi', 'pwd' => 'hello');
if($snoopy->submit('http://example.com/login', $login) === false) {
// output the response code
die($snoopy->response_code . ':' . $snoopy->error);
}
//Request succeeded (doesn't mean we are logged in)
// output the results
echo $snoopy->results;
// Check the results to see if you are logged in and
// Continue using $snoopy.
// It will pass the proper cookies for the next requests.
With the help of the cURL library?