Is there any way to restrict post requests to my REST API only to requests coming from my own mobile app binary? This app will be distributed on Google Play and the Apple App Store so it should be implied that someone will have access to its binary and try to reverse engineer it.
I was thinking something involving the app signatures, since every published app must be signed somehow, but I can't figure out how to do it in a secure way. Maybe a combination of getting the app signature, plus time-based hashes, plus app-generated key pairs and the good old security though obscurity?
I'm looking for something as fail proof as possible. The reason why is because I need to deliver data to the app based on data gathered by the phone sensors, and if people can pose as my own app and send data to my api that wasn't processed by my own algorithms, it defeats its purpose.
I'm open to any effective solution, no matter how complicated. Tin foil hat solutions are greatly appreciated.
Any credentials that are stored in the app can be exposed by the user. In the case of Android, they can completely decompile your app and easily retrieve them.
If the connection to the server does not utilize SSL, they can be easily sniffed off the network.
Seriously, anybody who wants the credentials will get them, so don't worry about concealing them. In essence, you have a public API.
There are some pitfalls and it takes extra time to manage a public API.
Many public APIs still track by IP address and implement tarpits to simply slow down requests from any IP address that seems to be abusing the system. This way, legitimate users from the same IP address can still carry on, albeit slower.
You have to be willing to shut off an IP address or IP address range despite the fact that you may be blocking innocent and upstanding users at the same time as the abusers. If your application is free, it may give you more freedom since there is no expected level of service and no contract, but you may want to guard yourself with a legal agreement.
In general, if your service is popular enough that someone wants to attack it, that's usually a good sign, so don't worry about it too much early on, but do stay ahead of it. You don't want the reason for your app's failure to be because users got tired of waiting on a slow server.
Your other option is to have the users register, so you can block by credentials rather than IP address when you spot abuse.
Yes, It's public
This app will be distributed on Google Play and the Apple App Store so it should be implied that someone will have access to its binary and try to reverse engineer it.
From the moment its on the stores it's public, therefore anything sensitive on the app binary must be considered as potentially compromised.
The Difference Between WHO and WHAT is Accessing the API Server
Before I dive into your problem I would like to first clear a misconception about who and what is accessing an API server. I wrote a series of articles around API and Mobile security, and in the article Why Does Your Mobile App Need An Api Key? you can read in detail the difference between who and what is accessing your API server, but I will extract here the main takes from it:
The what is the thing making the request to the API server. Is it really a genuine instance of your mobile app, or is it a bot, an automated script or an attacker manually poking around your API server with a tool like Postman?
The who is the user of the mobile app that we can authenticate, authorize and identify in several ways, like using OpenID Connect or OAUTH2 flows.
Think about the who as the user your API server will be able to Authenticate and Authorize access to the data, and think about the what as the software making that request in behalf of the user.
So if you are not using user authentication in the app, then you are left with trying to attest what is doing the request.
Mobile Apps should be as much dumb as possible
The reason why is because I need to deliver data to the app based on data gathered by the phone sensors, and if people can pose as my own app and send data to my api that wasn't processed by my own algorithms, it defeats its purpose.
It sounds to me that you are saying that you have algorithms running on the phone to process data from the device sensors and then send them to the API server. If so then you should reconsider this approach and instead just collect the sensor values and send them to the API server and have it running the algorithm.
As I said anything inside your app binary is public, because as yourself said, it can be reverse engineered:
should be implied that someone will have access to its binary and try to reverse engineer it.
Keeping the algorithms in the backend will allow you to not reveal your business logic, and at same time you may reject requests with sensor readings that do not make sense(if is possible to do). This also brings you the benefit of not having to release a new version of the app each time you tweak the algorithm or fix a bug in it.
Runtime attacks
I was thinking something involving the app signatures, since every published app must be signed somehow, but I can't figure out how to do it in a secure way.
Anything you do at runtime to protect the request you are about to send to your API can be reverse engineered with tools like Frida:
Inject your own scripts into black box processes. Hook any function, spy on crypto APIs or trace private application code, no source code needed. Edit, hit save, and instantly see the results. All without compilation steps or program restarts.
Your Suggested Solutions
Security is all about layers of defense, thus you should add as many as you can afford and required by law(e.g GDPR in Europe), therefore any of your purposed solutions are one more layer the attacker needs to bypass, and depending on is skill-set and time is willing to spent on your mobile app it may prevent them to go any further, but in the end all of them can be bypassed.
Maybe a combination of getting the app signature, plus time-based hashes, plus app-generated key pairs and the good old security though obscurity?
Even when you use key pairs stored in the hardware trusted execution environment, all an attacker needs to do is to use an instrumentation framework to hook in the function of your code that uses the keys in order to extract or manipulate the parameters and return values of the function.
Android Hardware-backed Keystore
The availability of a trusted execution environment in a system on a chip (SoC) offers an opportunity for Android devices to provide hardware-backed, strong security services to the Android OS, to platform services, and even to third-party apps.
While it can be defeated I still recommend you to use it, because not all hackers have the skill set or are willing to spend the time on it, and I would recommend you to read this series of articles about Mobile API Security Techniques to learn about some complementary/similar techniques to the ones you described. This articles will teach you how API Keys, User Access Tokens, HMAC and TLS Pinning can be used to protect the API and how they can be bypassed.
Possible Better Solutions
Nowadays I see developers using Android SafetyNet to attest what is doing the request to the API server, but they fail to understand it's not intended to attest that the mobile app is what is doing the request, instead it's intended to attest the integrity of the device, and I go in more detail on my answer to the question Android equivalent of ios devicecheck. So should I use it? Yes you should, because it is one more layer of defense, that in this case tells you that your mobile app is not installed in a rooted device, unless SafetyNet has been bypassed.
Is there any way to restrict post requests to my REST API only to requests coming from my own mobile app binary?
You can allow the API server to have an high degree of confidence that is indeed accepting requests only from your genuine app binary by implementing the Mobile App Attestation concept, and I describe it in more detail on this answer I gave to the question How to secure an API REST for mobile app?, specially the sections Securing the API Server and A Possible Better Solution.
Do you want to go the Extra Mile?
In any response to a security question I always like to reference the excellent work from the OWASP foundation.
For APIS
OWASP API Security Top 10
The OWASP API Security Project seeks to provide value to software developers and security assessors by underscoring the potential risks in insecure APIs, and illustrating how these risks may be mitigated. In order to facilitate this goal, the OWASP API Security Project will create and maintain a Top 10 API Security Risks document, as well as a documentation portal for best practices when creating or assessing APIs.
For Mobile Apps
OWASP Mobile Security Project - Top 10 risks
The OWASP Mobile Security Project is a centralized resource intended to give developers and security teams the resources they need to build and maintain secure mobile applications. Through the project, our goal is to classify mobile security risks and provide developmental controls to reduce their impact or likelihood of exploitation.
OWASP - Mobile Security Testing Guide:
The Mobile Security Testing Guide (MSTG) is a comprehensive manual for mobile app security development, testing and reverse engineering.
No. You're publishing a service with a public interface and your app will presumably only communicate via this REST API. Anything that your app can send, anyone else can send also. This means that the only way to secure access would be to authenticate in some way, i.e. keep a secret. However, you are also publishing your apps. This means that any secret in your app is essentially being given out also. You can't have it both ways; you can't expect to both give out your secret and keep it secret.
Though this is an old post, I thought I should share the updates from Google in this regard.
You can actually ensure that your Android application is calling the API using the SafetyNet mobile attestation APIs. This adds a little overhead on the network calls and prevents your application from running in a rooted device.
I found nothing similar like SafetyNet for iOS. Hence in my case, I checked the device configuration first in my login API and took different measures for Android and iOS. In case of iOS, I decided to keep a shared secret key between the server and the application. As the iOS applications are a little bit difficult to reversed engineered, I think this extra key checking adds some protection.
Of course, in both cases, you need to communicate over HTTPS.
As the other answers and comments imply, you cant truly restrict API access to only your app but you can take different measures to reduce the attempts. I believe the best solution is to make requests to your API (from native code of course) with a custom header like "App-Version-Key" (this key will be decided at compile time) and make your server check for this key to decide if it should accept or reject. Also when using this method you SHOULD use HTTPS/SSL as this will reduce the risk of people seeing your key by viewing the request on the network.
Regarding Cordova/Phonegap apps, I will be creating a plugin to do the above mentioned method. I will update this comment when its complete.
there is nothing much you can do. cause when you let some one in they can call your APIs. the most you can do is as below:
since you want only and only your application (with a specific package name and signature) calls your APIs, you can get the signature key of your apk pragmatically and send is to sever in every API call and if thats ok you response to the request. (or you can have a token API that your app calls it every beginning of the app and then use that token for other APIs - though token must be invalidated after some hours of not working with)
then you need to proguard your code so no one sees what you are sending and how you encrypt them. if you do a good encrypt decompiling will be so hard to do.
even signature of apk can be mocked in some hard ways but its the best you can do.
Someone have looked at Firebase App Check ?
https://firebase.google.com/docs/app-check
Is there any way to restrict post requests to my REST API only to requests coming from my own mobile app binary?
I'm not sure if there is an absolute solution.
But, you can reduce unwanted requests.
Use an App Check:
The "Firebase App Check" can be used cross-platform (https://firebase.google.com/docs/app-check) - credit to #Xande-Rasta-Moura
iOS: https://developer.apple.com/documentation/devicecheck
Android: https://android-developers.googleblog.com/2013/01/verifying-back-end-calls-from-android.html
Use BasicAuth (for API requests)
Allow a user-agent header for mobile devices only (for API requests)
Use a robots.txt file to reduce bots
User-agent: *
Disallow: /
Using Laravel for PHP and DBMS. How do I make an app? (for social networking).
I have googled most of the things but I am really an Amateur and need help.
There are many kinds of apps, so before you start to work on your app, you need to carefully determine what exactly you need. You could write desktop apps for various operating systems, or native mobile apps, or hybrids, or a web application... You name it. Anyway, Laravel is the server-side and it should be as agnostic to the apps as possible. You need to create an API and handle the following things:
CRUD for the database
session (log in, log out, register, password change, user settings)
logical API functions
file transfer protocol usage
push notification (if needed)
As per your requirements, you will need to implement the server-side API in Laravel, which is a PHP-based framework and use an RDBMS, which could be MySQL, SQL Server, Oracle, or a NoSQL database, for instance MongoDB.
Before you implement any apps, you should have a proof-of-concept for the API. You should not invest too much time working out the details of the API, as when you are going to work on a real app, you will notice things to be changed anyway. The API should be accompanied by a playground for testing, maybe a very small app without design where you could send requests to the API. Or you can implement a WebSocket API to have a single, duplex connection. It is up to you.
As about how to write an API, there are many tutorials.
I found myself in several discussions throughout the week regarding a web application under development and whether it should leverage an API that is being created.
Here's the situation. I have a PHP MVC web application with a MySQL DB as well as several mobile apps all being developed in house. For the mobile apps we're building a rest api. The big question is why should my PHP web application now use that rest api? I've always expected the use of an API to be for third party systems that need to interface with my database or for systems built on a different technology. The web app is certainly not a third party system and the services are in PHP. If the API is on a different server than the web app then I guess it could be considered a third party system... which has not been decided yet.
To me, it just seems strange to leverage the API for the web app especially since the APIs services are going to be limited to about 50% of the functions available in the web app leaving me to build the other 50% that would be unique to the web app. I also foresee a performance hit to the web app stepping through the service layer rather than just accessing the DB directly. On the other side I see more maintenance having a code base for my web app hitting the DB and similar functions built into the api for mobile apps.
Has anyone found themselves in a similar situation and can provide some technical pros and cons to why I should just use the API or can point me to a solid case study?
Pros:
What if one day you decide to move the backend app to another machine? With an API, your app code won't need to change.
What if one day you grow, and need to scale to 10000 backend apps instead of 1? With an API, your app code won't need to change.
What if one day you decide to swap out MySQL for Mongo? With an API, your app code won't need to change.
^ Enforced separation of concerns between data access layer (DB) and application
Cons:
More code up front when writing the app layer
More incremental work when you need to support a new app layer feature that your API doesn't support yet
To me, the pros clearly win.
I want to create following project :
Server application hosted on Azure - it connects to databse via Entity framework and gives and API for anyone who want to connect (but with account stored in SQL database)
WPF application - it consumes server methods, objects etc.
Web app (php & javascript) - also consumes server methods and object etc.
IMPORTANT : I have only azure student's subscription and I want to hold onto it - buying anything else is out of the question unless it has strong argumentation.
I figured that to do this I have to create REST Web API because I have no other choice to connect to server than via HTTPWebRequest (because I want to have the same API for WPF nad web app).
My question is : does better solution exists?
I think I can create different API's for desktop client than web app but I have no idea how to do that. Whould you be so kindly to show me other way?
Why dont I want to have this solution?
Reason is simple. For big databases and slow internet connection it would take ages to download whole data in few seconds. As far as my knowledge goes there is no lazy loading in REST thus my WPF application's thread reponsible for downloading database would freeze for a big period of time.
If my question is too broad please leave a comment before you put up a flag.
Also, any tips regarding my project design are well appreciated.
Different APIs for Desktop and Web: this can be done easily enough. Assume you have a class library to contain your business logic (domain stuff). Create a web api project that makes use of it, then create yet another web api project separately that also makes use of the core models. When you deploy, deploy each separately to a different domain/subdomain (I'm unsure if you'll require further Azure resources for this, but consider api.desktop.myapp.com and api.web.myapp.com... no real technical reason why you can't do it that way, though for architecture reasons I'd avoid it (it's really coming close to if not definitely is duplication of code).
Same API for Desktop and Web: you stated that you thought you'd have to do this differently for the desktop and web, specifically because of the resource usage on the server. I disagree here, and think you should implement some standardized rate limiting into your API. Typically this is done by allowing only X amount of resources to be returned in a single call. If the initial request asks for more than X limit, an offset/nextID is returned by the API, and the client submits a new request noting that offset/nextID. This means you have subsequent calls from the client to get everything it needs, but gives your server a chance to handle it in smaller chunks (e.g., check for rate limits, throttling, load balancing, etc). See the leaky bucket algorithm for an implementation that I prefer, myself: https://en.wikipedia.org/wiki/Leaky_bucket)
here is my scenario, i am building a web application using PHP and MySQL. basically it is a real estate application. where i would like to share the data among several other platforms and devices, here is i what i intend to do
a) building the web app to be used with the browser using PHP, MySQL, and AJAX. (this will be my server)
b) extend the support and build a desktop application using POKKI.
c) extend the support and build an application for Androids and iOS devices.
d) all data transaction for the app should take place from the web server.
e) basically it will be server client application . where the server will be my web server and the clients will be iOS app, Android App Pokki etc.
i am not a hardcore programmer, although it has been more then 1 year since i started using PHP, and i do understand it to my use. i would like to know the best feasible solution on how to share the data among the different clients(POKKI, iOS App, Android App).
i would like to know.
a) do i have to connect to database directly from the client and access the data? is it possible? is it bad if i go this way?
b) do i have to create a public class with api sign up process? what would be the real scenario if i would like it to make it cross platform.
A Humble request to all of you to guide me on how does this things works. any articles, resources, links that can prove useful to me will also be appreciated.
thank you.
I think you should create an API which allows you to access the database strictly as you want it. Look at the twitter API for example and see how it allows third parties to access their data using simple requests.
So your site uses the DB directly where as all other applications you want to make will use the API ( which runs on ur web server)
This would allow you with the flexibility to have control who gets access and who doesnt ( only your own apps or even third parties etc etc) and allows you to build kick-ass applications without putting your actual database at risk.
Hope this helps!
1 - you should not allow client to access data directly - bad.
2 - sign up are easy with open id, let google or any other openid provider handle authentication, you deal with your own clean code without worrying about auth.
http://code.google.com/apis/accounts/docs/OpenID.html
You can create xml api and share the data from your server.
On different type of client you can eaisly parse the xml data and process it or show it.
In xml API if you want the restrict access then your can provide the restriction.
Please let me know if you have any issue
Thanks and Regards,
Ankur K Singh
take a look into getfrapi.com for building API.