Is there any methods to prevent web client from filling my parse cloud storage with dummy files? As far i can see, the creation of Parse.File (without object reference) requires only valid api key which is plain text in client side. Does this imply that any others can impersonate to be my valid js client with the api key or did i miss out anything in the api reference?
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I have a project which I use Google Places API.
For the API key I have now, I have set IP restriction because the API is called in server-side. Place Search and Place Details are called in Server and returned to client side.
But the endpoint Place Photos, I call in client side, and of course it doesn't work because I have set IP restriction. So, my idea is to create one more production api key which works on client side and set HTTP referrers. Is this Ok? Or should I call all apis in server-side instead?
There is a lot of good content on the internet that explains how to secure a Spring API with Keycloak: Create a Client that represents the API Service in Keycloak and use a link like the one below to get the access and refresh token:
<Domain>/auth/realms/<realm>/protocol/openid-connect/auth/{some parameters}
This yields both tokens. So far so good.
Now, however, I am not sure how the flow for the frontend accessing the API should look like.
Should the frontend directly access this endpoint and, therefore, obtain the access and refresh token? That would mean that the API can only have the access-type public because there is no way to store the client (the API) secret securely.
Or should there be a third server that somehow stores the refresh token for each user, that the user can call if his access token is no longer valid. This server would then use the client's refresh token (and the client secret that could be stored securely, since it would be in the backend) to get a new access token from Keycloak and would forward it to the user.
I guess the main question that I am asking is, whether the client/user should get the refresh token.
If one needs to implement a logic according to the second option, I would be interested in a link or description of how something like this can be done in Spring.
I think, in either case you need to use the Authorization Code Flow. The implicit flow, which was recommended for SPAs (frontends without a backend server) in former versions of OAuth2 must not be used anymore.
The best option is to have a backend server, so the user retrieves the auth code via redirection and the backend server exchanges this auth code with the access and refresh tokens (and keep them without forwarding them to the frontend).
If there is no backend in place and your frontend needs to retrieve and hold the tokens directly, I would recommend to use the Authorization Code Flow with a public client and the PKCE extension (which - put simply - ensures that the entity asking for the auth code is the same as the entity asking for the tokens and that the auth code was not stolen and used by a foreign entity). There are several sources with more detailed explanations, which might help you, for example: https://auth0.com/docs/flows/authorization-code-flow-with-proof-key-for-code-exchange-pkce
Hope this helps you with your architectural considerations.
I have a client-side application on domain client-domain.example and a server-side application on domain server-domain.example. There is an API on the server-side. The client-side application sends AJAX requests to the server-side application. I use token-based authentication, so the client-side application sends token in headers with each AJAX request, for example: "Authorization: Bearer {some token}". It works fine with AJAX requests, when I need to get or post some data.
But the server-side API also keeps files. For example images. The files are private, only authenticated users can get them. And I need to show this images on the client-side in <img> tag. I can't get them using <img src="http://server-domain.example/path/to/image"> because in this case browser will not send Authorization header to the server-side.
What is the adopted solution? How client applications load images from server-side API?
There are three methods to solve it, the best approach to solve it is using the signed URLs
1. signed URL (can be insecure)
The first method simply creates a route without authentication (anonymous access) with a signature hash parameter that indicates if the resource can be loaded or not.
<img src="http://server-domain.example/path/to/image?guid=f6fc84c9f21c24907d6bee6eec38cabab5fa9a7be8c4a7827fe9e56f2">
When the server receives the request it must validate the guid if the expiration time has not been reached and, of course, check if the guid has a valid signature.
This approach is used by several files/documents servers like Dropbox, S3, CDN providers, etc.
See the technique in some companies.
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/private-content-signed-urls.html#private-content-overview-choosing-duration
https://client.cdn77.example/support/knowledgebase/cdn-resource/how-do-i-set-up-signed-urls
SECURITY:
the guid can not be just UUID of the image/user, because this doesn't provide any protection.
the guid can not be the same token you use for authentication (for example, you can't use auth-JWT tokens), because the user can share the link - and the user will share his tokens (see also (2)).
as mentioned above: guid should have a server-side mechanism of validation (date/signature/...) and should not provide more permissions than "access to the requested file"
2 Query String with JWT (most probably a security breach)
The second method is to pass the token by querystring with the image URL.
This method is not recommendable because it exposes clearly the URL and many servers sometimes write and expose public logs of URL accessed. The bad notice is that the JWT exposed normally the user can get control a lot of features further the image load.
<img src="http://server-domain.example/path/to/image?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c">
When the server receives the request you must validate the token by querystring and response with the content.
SECURITY NOTES: worse than (1) - because now authentication info (JWT auth) is exposed in the URL and can be cached/logged by servers OR accessed by any server in the middle OR the user can simply share the "image link" with their colleagues.
But if JWT is NOT an access token, but a one-time token generated specifically for accessing that particular file in a form of JWT then it provides the same level of security as (1).
3. cookies
The third method creates an authenticated cookie to validate the access of the image.
This method is not recommendable because is out of API pattern (webapi/token based authentication in general).
When the server receives the request you need to validate if the validate cookie is valid.
SECURITY NOTES: if you can provide security for your cookies and XSS and CSRF — are not just letters for you then it is a solution. But keep in mind: cookies are sent by the browser automatically with each request. Much more information about possible threats and solutions: Where to store JWT in browser? How to protect against CSRF?
My solution to basically this exact same problem, based on Jeferson Tenorio's answer below (option 1), was to sign the URL to my API call with an encryption of the image and the user's JWT token, e.g. path/to/image?token=xxxx. In laravel this is easily accomplished with encrypt($your_object) and decrypt($token) (https://laravel.com/docs/5.7/encryption), and then I used the extracted token to verify the user had access to the file in question. But there are probably many other libraries capable of handling this.
I would be curious if there are any security concerns, but from my perspective the JWT is never exposed via plain text and the encryption relies on a secret key that malicious actors shouldn't have access to, so it seems like it should be fairly secure. My only real complaint is that the token is quite long using this method which does not make for presentable URLs.
I am trying to handle file uploads for a web app through cloud code.I am facing the following issues
We cant add third party middle ware such as busboy to parse
Express' built in function such as req.files doesn't seem to work with the body parser parse.com provides.
I don't want to expose my app key in the client code.
I wanted to know if there is any other way to handle this.
Parse Cloud is not a Node environment so it is not a surprise that it does not support nmp modules.
The middleware Parse provides for express.js does not support file uploads. Instead you need to send the file contents as base64 to your endpoint and create the Parse.File object from this data. more info here
Your app and client keys(except for master key) are PUBLIC INFORMATION and NOT secrets. This is clearly mentioned in the documentation by Parse and you cannot hide them at all. Use CLPs, ACLs and Cloud code to protect your data from unauthorised access.
I am about to start working on a project, which is basically a web interface for a mobile banking application. The API is ready, I only need to provide the frontend part of the web application. I was going to make it using Backbone/Angular/Ember, but started to worry about the security.
Particularly, the following. As a rule, every API request must contain a parameter method_code, which is calculated as hash of user token, method name and secret API key. If I put the logic of how this param is calculated into one of .js files, anyone could potentially access some sensitive data using tools like Postman or even browser console. How should I go about this issue? I could have a server-side script generating the method_code for me, but is it possible to make it accessible only to my web app's requests?
every API request must contain a parameter method_code, which is calculated as hash of user token, method name and secret API key
I could have a server-side script generating the method_code for me, but is it possible to make it accessible only to my web app's requests?
Yes, the server-side script would be the way to go if you do not want to expose the secret API key within your client side code or request data.
User token can (presumably) come from the user's session cookie value? So simply have a server side method that takes the method name and then returns the method_code calculated from the secret API key (kept server side only) and the user token.
The Same Origin Policy will prevent another domain making a request to your API and retreiving the method_code. I'm also assuming the API and front-end code runs on the same domain here, although if this is not the case you can use CORS to allow your front-end code to read and retreive data client-side via the API.
You can try to generate a token based on security factors and encrypt that and use it in your requests to identify your clients and valid requests.