I'd like to set my Google pay to accept both authentication modes: "PAN_ONLY" and "CRYPTOGRAM_3DS".
Then, during transaction flow, when I get the token, before I process the transaction - how can I check which authentication mode was applied by google out of the 2 without decrypting the token?
Why I want to do that:
if it's was tokenized in a 'PAN_ONLY' mode, I need to run 3DSecure myself, before processing the transaction
if it's 'CRYPTOGRAM_3DS' it means that the token is in DPAN mode and then I'd like to decrypt it (as a merchant)
how can I check which authentication mode was applied by google out of the 2 without decrypting the token?
You can request this information in the request with the CardParameters. assuranceDetailsRequired parameter. It will be returned as part of the CardInfo.assuranceDetails response.
if it's was tokenized in a 'PAN_ONLY' mode, I need to run 3DSecure myself, before processing the transaction
From https://developers.google.com/pay/api/web/reference/response-objects#assurance-details-specifications
Note: If both cardHolderAuthenticated and accountVerified are true, you don’t need to step up the returned credentials. If both aren’t, we recommend you to run the same risk checks and , authentication including 3D Secure flow if applicable.
Related
I'm trying to understand cookie vs token-based authentication. I get the basics - cookies have to be stored in the server (as well as the client) to be verified each time, whereas tokens only have to be stored on the client-side. The server simply decodes any incoming tokens and verifies the request.
What I don't understand is, how does the server know whether any decoded token is valid, if a list of valid tokens isn't being stored anywhere in the server?
https://dzone.com/articles/cookies-vs-tokens-the-definitive-guide
User enters their login credentials.
Server verifies the credentials are correct and returns a signed token.
This token is stored client-side, most commonly in local storage - but can be stored in session storage or a cookie as well.
Subsequent requests to the server include this token as an additional Authorization header or through one of the other methods mentioned above.
The server decodes the JWT and if the token is valid processes the request.
Once a user logs out, the token is destroyed client-side, no interaction with the server is necessary.
To be specific - I'd like to know how #5 works. Thank you.
A full answer to your question would be very long, but here is my attempt at a brief one. The server also happens to be the entity which issues the JWT in the first place. As such, it possesses a key which it used to sign each outgoing JWT. As a result of this, when the server receives an incoming JWT, it first tries to open/unlock that JWT using its private key. If the JWT were tampered with in any way, the server might not be able to open it properly, and it would result in an exception. As an example of one sanity check the server would perform against an incoming JWT, it would observe the checksum of the JWT, would not pass in the case of tampering.
Once the server has opened the JWT and deemed it to be valid, the next thing it would likely check would be the exp claim, one of possibly several claims which are contained within the JWT. The exp, or expiry, claim, records for how long the JWT is valid. Should a user present a stale JWT, the server would immediately reject the JWT as being invalid.
So far, we have been discussing checks the server may perform using no state, that is, relying only on the state contained within the JWT itself. In reality, most of the time the server would in fact be storing some state of its own. As an example of why this might be necessary, consider the edge case of a user who logs out of the site or app. In this situation, his phone or browser would still be bearing a JWT with a valid exp expiry. In order to prevent the user from continuing to use this JWT, the server might maintain a blacklist of JWT which it will not honor, even if the exp and checksum pass inspection. So, a third step after unlocking the JWT and checking exp might be to make sure that the JWT does not appear on the blacklist.
A good JWT implementation can limit the amount of server side state to something very small, but typically the server would actually maintain some state of its own.
I am building an API that will authenticate using the following flow.
Endpoints:
WWW:/login - this is the HTML5 frontend using JS ajax calls
API:/check_password - checks email/password combo.
API:/check_otp - checks OTP (One-time password) for user.
API:/login - sets authentication session cookie
Assumption:
API:/check_otp will always and only ever be called after API:/check_password.
Ignore CSRF attacks and XSS attacks.
Even if the frontend (WWW:/login) is malicious, the API will only work with valid credentials and/or action_tokens.
I am aware of OAuth2, JWTs, and RESTful APIs. My question is not about RESTful API.
When logging in, the flow would be this:
WWW:/login submits email and password to API:/check_password.
If the credentials are valid, API:/check_password will return an action_token and mfa_status (stands for Multi-factor authentication).
If mfa_status is 0, that means MFA is not enabled.
If mfa_status is 1, that means MFA is enabled.
If (mfa_status === 1), then WWW:/login will call API:/check_otp and pass it the action_token received from API:/check_password as well as the OTP.
If the OTP and action_token are valid, then API:/check_otp will return a new action_token.
If (mfa_status === 0) or API:/check_otp returns a valid action_token, then WWW:/login will call API:/login and pass to it the email and action_token.
To me, this means the frontend does NOT need to save the password or OTP anywhere in its data stores (localstorage, indexeddb, etc). It also means it can immediately remove the action_token from its data stores.
QUESTIONS:
Is this secure?
Are there any flaws in this logic?
Did I miss anything?
Many thanks for an interesting and thorough discussion!
Your pattern directly maps to OAuth2, why would you not use a tried-and-true security pattern like OAuth2? You are trying to rebuild it for some reason... your action_token is the same as the OAuth access token.
Also, you will need to keep your access token for subsequent calls to protected resources (you know like OAuth does)...
All you are doing is making more work for yourself by not either using an out-of-the-box OAuth library, or obfuscating the process to make the next person to update this code cranky with you.
I have been reading about securing REST APIs and have read about oAuth and JWTs. Both are really great approaches, but from what I have understood, they both work after a user is authenticated or in other words "logged in". That is based on user credentials oAuth and JWTs are generated and once the oAuth token or JWT is obtained the user can perform all actions it is authorized for.
But my question is, what about the login and sign up apis? How does one secure them? If somebody reads my javascript files to see my ajax calls, they can easily find out the end points and the parameters passed, and they could hit it multiple times through some REST Client, more severely they could code a program that hits my sign up api say a thousand times, which would be create a thousand spam users, or they could even brute force the login api. So how does one secures them?
I am writing my API in yii2.
The Yii 2.0 framework has a buil-in filter called yii\filters\RateLimiter that implements a rate limiting algorithm based on the leaky bucket algorithm. It will allow you to limit the maximum number of accepted requests in a certain interval of time. As example you may limit both login and signup endpoints to accept at most 100 API calls within a 10 minutes interval of time. When that limit is exceeded a yii\web\TooManyRequestsHttpException exception (429 status code) will be thrown.
You can read more about it in the Yii2 RESTful API related documentation or within this SO post.
I didn't use it myself so far but from what I did read about it in official docs, and I mean this:
Note that RateLimiter requires
$user
to implement the
yii\filters\RateLimitInterface.
RateLimiter will do nothing if
$user
is not set or does not implement
yii\filters\RateLimitInterface.
I guess it was designed to work with logged in users only maybe by using the user related database table, the default one introduced within the advanced template. I'm not sure about it but I know it needs to store the number of allowed requests and the related timestamp to some persistent storage within the saveAllowance method that you'll need to define in the user class. So I think you will have to track your guest users by IP addresses as #LajosArpad did suggest then maybe redesigning your user class to hold their identities so you can enable it.
A quick google search let me to this extension:yii2-ip-ratelimiter to which you may also have a look.
Your URLs will easily be determined. You should have a black list of IP addresses and when an IP address acts suspiciously, just add it to the black list. You define what suspicious is, but if you are not sure, you can start with the following:
Create something like a database table with this schema:
ip_addresses(ip, is_suspicious, login_attempts, register_attempts)
Where is_suspicious means it is blacklisted. login_attemtps and register_attempts should be json values, showing the history of that ip address trying to log in/register. If the last 20 attempts were unsuccessful and were within a minute, then the ip address should be blacklisted. Blacklisted ip addresses should receive a response that they are blacklisted whatever their request was. So if they deny your services or try to hack things, then you deny your services from them.
Secure passwords using sha1, for example. That algorithm is secure-enough and it is quicker than sha256, for instance, which might be an overkill. If your API involves bank accounts or something extremely important like that, important-enough for the bad guys to use server parks to hack it, then force the users to create very long passwords, including numbers, special characters, big and small letters.
For javascript you should use OAuth 2.0 Implicit Grant flow like Google or Facebook.
Login and Signup use 2 basic web page. Don't forget add captcha for them.
For some special client such as mobile app or webServer:
If you sure that your binary file is secure, You can create a custom login API for it. In this API you must try to verify your client.
A simple solution, you can refer:
use an encryption algorithm such as AES or 3DES to encrypt password
from client use a secret key (only client and server knows about it)
use a hash algorithm such as sha256 to hash (username + client time + an other
secret key). Client will send both client time and hash string to
server. Server will reject request if client time is too different
from server or hash string is not correct.
Eg:
api/login?user=user1&password=AES('password',$secret_key1)&time=1449570208&hash=sha256('user1'+'|'+'1449570208'+'|'+$secret_key2)
Note: In any case, server should use captcha to avoid brute force attack, Do not believe in any other filter
About captcha for REST APIs, we can create captcha base on token.
Eg.
For sign up action: you must call 2 api
/getSignupToken : to get image captcha url and a signup token
respectively.
/signup : to post sign up data (include signup token and
captcha typed by user)
For login action: we can require captcha by count failed logins base on username
Folow my api module here for reference. I manager user authentication by access token. When login, i generate token, then access again, client need send token and server will check.
Yii2 Starter Kit lite
I know this is not the first time the topic is treated in StackOverflow, however, I have some questions I couldn't find an answer to or other questions have opposed answers.
I am doing a rather simple REST API (Silex-PHP) to be consumed initially by just one SPA (backbone app). I don't want to comment all the several authentication methods in this question as that topic is already fully covered on SO. I'll basically create a token for each user, and this token will be attached in every request that requires authentication by the SPA. All the SPA-Server transactions will run under HTTPS. For now, my decision is that the token doesn't expire. Tokens that expire/tokens per session are not complying with the statelessness of REST, right? I understand there's a lot of room for security improvement but that's my scope for now.
I have a model for Tokens, and thus a table in the database for tokens with a FK to user_id. By this I mean the token is not part of my user model.
REGISTER
I have a POST /users (requires no authentication) that creates a user in the database and returns the new user. This complies with the one request one resource rule. However, this brings me certain doubts:
My idea is that at the time to create a new user, create a new token for the user, to immediately return it with the Response, and thus, improving the UX. The user will immediately be able to start using the web app. However, returning the token for such response would break the rule of returning just the resource. Should I instead make two requests together? One to create the user and one to retrieve the token without the user needing to reenter credentials?
If I decided to return the token together with the user, then I believe POST /users would be confusing for the API consumer, and then something like POST /auth/register appears. Once more, I dislike this idea because involves a verb. I really like the simplicity offered in this answer. But then again, I'd need to do two requests together, a POST /users and a POST /tokens. How wrong is it to do two requests together and also, how would I exactly send the relevant information for the token to be attached to a certain user if both requests are sent together?
For now my flow works like follows:
1. Register form makes a POST /users request
2. Server creates a new user and a new token, returns both in the response (break REST rule)
3. Client now attaches token to every Request that needs Authorization
The token never expires, preserving REST statelessness.
EMAIL VALIDATION
Most of the current webapps require email validation without breaking the UX for the users, i.e the users can immediately use the webapp after registering. On the other side, if I return the token with the register request as suggested above, users will immediately have access to every resource without validating emails.
Normally I'd go for the following workflow:
1. Register form sends POST /users request.
2. Server creates a new user with validated_email set to false and stores an email_validation_token. Additionally, the server sends an email generating an URL that contains the email_validation_token.
3. The user clicks on the URL that makes a request: For example POST /users/email_validation/{email_validation_token}
4. Server validates email, sets validated_email to true, generates a token and returns it in the response, redirecting the user to his home page at the same time.
This looks overcomplicated and totally ruins the UX. How'd you go about it?
LOGIN
This is quite simple, for now I am doing it this way so please correct me if wrong:
1. User fills a log in form which makes a request to POST /login sending Basic Auth credentials.
2. Server checks Basic Auth credentials and returns token for the given user.
3. Web app attached the given token to every future request.
login is a verb and thus breaks a REST rule, everyone seems to agree on doing it this way though.
LOGOUT
Why does everyone seem to need a /auth/logout endpoint? From my point of view clicking on "logout" in the web app should basically remove the token from the application and not send it in further requests. The server plays no role in this.
As it is possible that the token is kept in localStorage to prevent losing the token on a possible page refresh, logout would also imply removing the token from the localStorage. But still, this doesn't affect the server. I understand people who need to have a POST /logout are basically working with session tokens, which again break the statelessness of REST.
REMEMBER ME
I understand the remember me basically refers to saving the returned token to the localStorage or not in my case. Is this right?
If you'd recommend any further reading on this topic I'd very much appreciate it. Thanks!
REGISTER
Tokens that expire/tokens per session are not complying with the statelessness of REST, right?
No, there's nothing wrong with that. Many HTTP authentication schemes do have expiring tokens. OAuth2 is super popular for REST services, and many OAuth2 implementations force the client to refresh the access token from time to time.
My idea is that at the time to create a new user, create a new token for the user, to immediately return it with the Response, and thus, improving the UX. The user will immediately be able to start using the web app. However, returning the token for such response would break the rule of returning just the resource. Should I instead make two requests together? One to create the user and one to retrieve the token without the user needing to reenter credentials?
Typically, if you create a new resource following REST best practices, you don't return something in response to a POST like this. Doing this would make the call more RPC-like, so I would agree with you here... it's not perfectly RESTful. I'll offer two solutions to this:
Ignore this, break the best practices. Maybe it's for the best in this case, and making exceptions if they make a lot more sense is sometimes the best thing to do (after careful consideration).
If you want be more RESTful, I'll offer an alternative.
Lets assume you want to use OAuth2 (not a bad idea!). The OAuth2 API is not really RESTful for a number of reasons. I'm my mind it is still better to use a well-defined authentication API, over rolling your own for the sake of being RESTful.
That still leaves you with the problem of creating a user on your API, and in response to this (POST) call, returning a secret which can be used as an access/refresh token.
My alternative is as follows:
You don't need to have a user in order to start a session.
What you can do instead is start the session before you create the user. This guarantees that for any future call, you know you are talking to the same client.
If you start your OAuth2 process and receive your access/refresh token, you can simply do an authenticated POST request on /users. What this means is that your system needs to be aware of 2 types of authenticated users:
Users that logged in with a username/password (`grant_type = passsword1).
Users that logged in 'anonymously' and intend to create a user after the fact. (grant_type = client_credentials).
Once the user is created, you can assign your previously anonymous session with the newly created user entity, thus you don't need to do any access/refresh token exchanges after creation.
EMAIL VALIDATION
Both your suggestions to either:
Prevent the user from using the application until email validation is completed.
Allow the user to use the application immediately
Are done by applications. Which one is more appropriate really depends on your application and what's best for you. Is there any risk associated with a user starting to use an account with an email they don't own? If no, then maybe it's fine to allow the user in right away.
Here's an example where you don't want to do this: Say if the email address is used by other members of your system to add a user as a friend, the email address is a type of identity. If you don't force users to validate their emails, it means I can act on behalf of someone with a different email address. This is similar to being able to receive invitations, etc. Is this an attack vector? Then you might want to consider blocking the user from using the application until the email is validated.
You might also consider only blocking certain features in your application for which the email address might be sensitive. In the previous example, you could prevent people from seeing invitations from other users until the email is validated.
There's no right answer here, it just depends on how you intend to use the email address.
LOGIN
Please just use OAuth2. The flow you describe is already fairly close to how OAuth2 works. Take it one step further an actually use OAuth2. It's pretty great and once you get over the initial hurdle of understanding the protocol, you'll find that it's easier than you thought and fairly straightforward to just implement the bits you specifically need for your API.
Most of the PHP OAuth2 server implementations are not great. They do too much and are somewhat hard to integrate with. Rolling your own is not that hard and you're already fairly close to building something similar.
LOGOUT
The two reasons you might want a logout endpoint are:
If you use cookie/session based authentication and want to tell the server to forget the session. It sounds like this is not an issue for you.
If you want to tell the server to expire the access/refresh token earlier. Yes, you can just remove them from localstorage, and that might be good enough. Forcing to expire them server-side might give you that little extra confidence. What if someone was able to MITM your browser and now has access to your tokens? I might want to quickly logout and expire all existing tokens. It's an edge case, and I personally have never done this, but that could be a reason why you would want it.
REMEMBER ME
Yea, implementing "remember me" with local storage sounds like a good idea.
I originally took the /LOGON and /LOGOUT approach. I'm starting to explore /PRESENCE. It seems it would help me combine both knowing someone's status and authentication.
0 = Offline
1 = Available
2 = Busy
Going from Offline to anything else should include initial validation (aka require username/password). You could use PATCH or PUT for this (depending how you see it).
You are right, SESSION is not allowed in REST, hence there is no need to login or logout in REST service and /login, /logout are not nouns.
For authentication you could use
Basic authentication over SSL
Digest authentication
OAuth 2
HMAC, etc.
I prefer to use PUBLIC KEY and PRIVATE KEY [HMAC]
Private key will never be transmitted over web and I don't care about public key. The public key will be used to make the user specific actions [Who is holding the api key]
Private key will be know by client app and the server. The private key will be used to create signature. You generate a signature token using private key and add the key into the header. The server will also generate the signature and validate the request for handshake.
Authorization: Token 9944b09199c62bcf9418ad846dd0e4bbdfc6ee4b
Now how you will get private key? you have to do it manually like you put facebook, twitter or google api key on you app.
However, in some case you can also return [not recommended] the key only for once like Amazon S3 does. They provide "AWS secret access key" at the registration response.
I have built a simple test API for a CakePHP application that will let a user login from a mobile device (or any device for that matter) and get a JSON response. This API could be used for a mobile app built in PhoneGap.
The login method looks like so:
public function login()
{
if($this->request->is('post'))
{
// Use custom method in Model to find record with password params
$findUser = $this->User->findUser(
$_POST['username_or_email'],
AuthComponent::password($_POST['password'])
);
// If a user exists and matches params
if($findUser)
{
$this->User->id = $findUser['User']['id'];
$this->autoRender = false;
$this->response->type('json');
$this->response->body(json_encode(array('authenticated'=>true,'message'=>__('You have been logged in successfully'))));
}
else
{
$this->autoRender = false;
$this->response->type('json');
$this->response->body(json_encode(array('authenticated'=>false,'message'=>__('Username or password is incorrect'))));
}
}
else
{
$this->autoRender = false;
$this->response->type('json');
$this->response->body(json_encode(array('message'=>'GET request not allowed!')));
}
}
The mobile device (or any API user) can send their login details and then they get the request as JSON as true or false for authenticated. This boolean is NOT used to give the user access, it instead tells the mobile app if they can see certain screens and they ONLY get the data or can send data if the session exists!
As just stated, they are also actually logged into the API itself on the device so if they visit the website directly (from that device) they will have a session and see the same response for the JSON.
So essentially a user remains logged in for the duration of the session on the device they communicated with the server on. This is different to a token which would need to be passed for every request, where as in this example they have a session.
Now the questions...
Is it bad practice for the user to be 'actually' logged into the API
with a session like shown above? It seems like the most secure way to handle authentication for a device as it's using the same logic as the direct web root.
I've seen some APIs use access tokens instead which I've also
implemented (user gets their token returned instead of the boolean
and no session is created). But from what I can tell, this seems
like more work as then I need to check for the access token against
a user record every time a request is made.
edit
For the sake of clarity, I am not a supporter of REST, I AM a supporter of RESTful/RESTlike services. If you look at all of the API's on the internet, very few actually stick to one standard. Whatever scheme you choose will depend on your specific problem-space. Just try to be secure and use intuitive design choices (ie dont name a service "cats" if it returns info about "dogs")
end edit
It is good practice in RESTful API's to manage some form of session/tokenizing scheme. Really the ideal (at least in my opinion, there are many schools of thought on this problem) setup involves rolling tokens.
If you are at all concerned with the security of your API, then permissions should be managed out of your database layer. Yes, this creates a bottleneck, BUT THAT IS ACTUALLY A GOOD THING. Needing to hit the database every single time to validate a client's token adds an extra step in the entire process. This slows down the API, which is actually desireable in a secure system. You don't want a malicious individual to be able to hit your API 3000 times a second, you want their requests to hang for a (somewhat) sizeable fraction of a second.
This is similar to MD5 hashing algorithms. Many of them recalculate the hash a few hundred times, with random pauses in between. This helps to keep a malicious client from attempting to brute force a password (by making it take more time to test each variation of the password string). The same applies to your API.
The other benefit, is that if you DO have a malicious user trying to log in over and over again, if you are managing them from the database layer, then you can red flag their IP Address/username/what-have-you and just drop their requests at step 1.
Anyway, for a suggested process (with rolling tokens, you can cut out parts of this if it seems overkill, but this is hella secure):
User hits a 'login' service, this requires a username/password, and returns two tokens, a Private Access Token and a Public Request Token (the server stores these tokens in the db).
The client stores these Tokens in a secure place
User accesses another endpoint to push/pull some data
Request includes a timestamp
Request includes the Public Request Token
Request includes an Access Token=> This token should be a MD5 hash of the string resulting from concatenating the timestamp string to the end of the Private Access Token string
The server takes the Public Request Token, uses that to lookup the Private Access Token that was stored
The server takes that Private Access Token, and concatenates on the Timestamp String, it then takes the MD5 of this string
If the new Access Token matches the one that the client sent the server, HURRAY, this client is validated, so push/pull the data
(Optional) The server generates new tokens on every request, and returns them to the client. This way every transaction invalidates the old tokens, and if there was some kind of man-in-the-middle attack occurring, if the VALID user has already completed their request, the malicious user now has invalid tokens and can't start messing with your API. This scheme tries to ensure that a malicious user can not expect to intercept a single communication between the server and the client, and still gain access to the system. If they do, then the REAL user should immediately get invalidated tokens. Which should then trigger their API client to hit the 'login' service AGAIN, getting new valid tokens. This once again kicks the malicious user out of the system.
This scheme is not 100% secure, no user access system ever will be. It can be made more secure by adding expiration dates on tokens. This scheme also has the added benefit that you can assign specific permissions to users/tokens (ie Read-Only access, only certain End-Points can be seen, etc)
This is not the only way you can do things, I would look up other Authentication Schemes and take what you want from each of them (OAUTH is a good place to start, then I'd look at Facebook/Twitter/Instagram)
Make your app login everytime, but not with login-pass pair as Swayok lastly suggested. When you login, server generates a token and returns it back to the client. Client then uses this token whenever it makes a request. On each request, server checks whether the token is valid and if so, executes the request.
This is very similar to how sessions work in that, server side frameworks manage it internally and these tokens expire from time to time. However, as Swayok rightuflly pointed out, you don't want session mainly because you're RESTful API should have no state. You get the same utility without storing any user specific data regarding user and logging user in with every request.
Here's a good article on this, or you can try the Facebook Graph API explorer to see it in action
Restful API restricts using sessions and saving system state at all. Each request must log-in user.
Access tokes are great but also require additional handling.
The easiest way is to send authorisation data via HTTP Basic Auth ("Authorization" HTTP header)
http://www.httpwatch.com/httpgallery/authentication/
Mobile Applications can easily do that and it is easy to add this header for each request to API.
On server side:
$username = env('PHP_AUTH_USER');
$password = env('PHP_AUTH_PW');
And process user log-in with this data in ApiAppController->beforeFilter()
To answer your questions
Its not a bad practice as long as you close their session on app close and recreate it when needed. it is same as if they were logged in on a browser they would know and have facility to log out however the same should be available on the app as well otherwise they might have closed the app but not actually ended their session. You can handle this in many ways by asking them to log out automatic checking when they close app
Tokens are an enhanced way of doing the above however you have to consider how secure the token is when transmitted and server need to verify the token on each request. You have said that it seems like more work so yes its more work and if you have time or money constrains and looking for an answer to say if the session style would harm your application in future it wont as long as you are in control of session and not leaving user without ending the session. If you have time then implement tokens and you would like that.