In a multi-tenant system where we have multiple customers. Each of those customers will have multiple users. What's the best way to ensure users from customer1 can never access data that belongs to customer2. We do have customer_id in all of our tables. I came across fine-grained access control but not sure if it could be used for this use-case. If not, what are my options? What are the best-practices to ensure security here?
Here is a relevant reference to your use case, please see the dynamodb:LeadingKeys. Assuming you are doing CRUD operations against tables that has customer as hash key and users as range keys.
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We are building a multi-tenant cloud-based web product where customer data is stored in single Database instance. There are certain portion of customer specific business data which is highly sensitive. The sensitive business data should be protected such that nobody can access it except the authorized users of the customer (neither through application not through accessing Database directly). Customer want to make sure even the platform provider(us) is not able to access specific data by any means. They want us to clearly demonstrate Data security in this context. I am looking for specific guidance in the following areas:
How to I make sure the data is protected at Database level such that even the platform provider cannot access the data.
Even if we encrypt the Data, the concern is that anyone with the decryption key can decrypt the data
What is the best way to solve this problem?
Appreciate your feedback.
"How to I make sure the data is protected at Database level such that even the platform provider cannot access the data"
-- As you are in a Multi-Tenanted environment, First of all you would have to "single tenant your databases" so one DB per customer. Then you need to modify the application to pick up the database from some form of config.
For encryption as you are in Azure you would have to use the Azure Key vault with your own keys or customer's own keys. you then configure SQL to use these keys to encrypt the data. see here and here
if you want the database to stay multi-tenanted, you would need to do the encryption at the application level. However this would need the application to know about customer keys, hence I dont think that this would be a valid solution.
"Even if we encrypt the Data, the concern is that anyone with the decryption key can decrypt the data" - yep anyone with the keys can access the data. For this you would need to set the access controls appropriately on your key vault.. so the customer can see only their keys.
In the end as you are the service provider.. the customers would have to trust you some what :)
I'm trying to create a service based on an Azure SQL Database backend.
The service will be multi-tenant, and would contain highly sensitive information from multiple "clients" (potentially hundreds of thousands), that must be strictly isolated from one another and secured heavily against data leaks. "by design"
Using so many individual databases would not be feasible, as there will be a lot of clients with very little information per client.
I have looked into the transparent encryption offered by Azure, but this would essentially encrypt the whole database as one, so it would in other words not protect against leaks between clients or someone else; due to development errors, or hostile attacks, and it's very critical that one "client's" information never comes into anyone else's hands.
So what I would really like to achieve, is to encrypt each client's data in the database with a different key, so that you would have to obtain the key from each client (from their "physical" location) to de-crypt any data you might manage to extract from the database for that particular client, which would be virtually impossible for anyone to do.
Is it clear what I mean?
Do you guys have any suggestions for me on how to manage this problem, or know of any third party solution that allows for this functionality? Any other advise?
You're looking at protecting/isolating the tenants "by design" in a single table, why not check out Row Level Security. You could configure it to serve up only the applicable rows to a specific tenant.
This doesn't directly address your initial question about encrypting the data with a separate key for each tenant; If you have a separate table for each tenant, then you could do this via Always Encrypted, but this would seem to have some complexity in key management, if you're trying to handle 200k keys.
AFAIK, there isn't a native SQL Server functionality to encrypt each set of rows that belongs to a tenant with a distinct key- but there may be some elegant solutions that I haven't seen yet; Of course, you could do this on the app side and store it in SQL and there would be no issues; the trick would be the same as the AE based solution above- managing a large number of keys.
I'm currently studying web security, purely on my own, to expand my skillset going forward in my career. I've been studying different encryption techniques, how best to employ them, etc.
The current situation I'm thinking about involves a multi-tenant database. Each schema in the database represents a different tenant. The data in each schema needs to be secured not only from outsiders, but from the other tenants as well.
To do this, I would use symmetric encryption, with a different key for each schema. But that's where my question comes in.
There are two ways to handle the keys, as I see it. One would be to have a secure location for storing the keys, like on a separate server. That would still require storing each and every key.
The second way would be re-generating the encryption key each time. The key would be a combination of a series of values related to the tenant that are stored in the database. Each time someone connects to the application, the key is re-generated by putting those values in the exact same order and hashing them.
I'm wondering if the second idea is overkill, or if it is a viable option. In general, though, I'm looking for guidance on how best to design database security policies.
Thank you.
My company is building an ASP.NET HR application and we have decided to create one database per client. This ensures that clients cannot accidentally view another client's data, while also allowing for easy scalability (among other benefits, already discussed here).
My question is - what is the best way to handle security and data access in such a scenario? My intent is to use a common login/account database that will direct the user to the correct server/database. This common database would also contain the application features that each user/role has access.
I was not planning to put any user information in each individual client database, but others on my team feel that the lack of security on each database is a huge hole (but they cannot articulate how duplicating the common access logic would be useful).
Am I missing something? Should we add an extra layer of security/authentication at the client database level?
Update:
One of the reasons my team felt dual user management was necessary is due to access control. All users have a default role (e.g. Admin, Minimal Access, Power User, etc.), but client admins will be able to refine permissions for users with access to their database. To me it still seems feasible for this to be in a central database, but my team doesn't agree. Thoughts?
We have a SaaS solution that uses the one DB per client model. We have a common "Security" database too. However, we store all user information in the individual client databases.
When the user logs into the system they tell us three pieces of information, username, password and client-id. The client-id is used to lookup their home database in the "security" database, and then the code connects to their home database to check their username/password. This way a client is totally self-contained within their database. Of course you need some piece of information beyond username to determine their home database. Could be our client-id approach, or could be the domain-name requested if you're using the sub-domain per client approach.
The advantage here is that you can move "client" databases around w/out having to keep them synced up with the security database. Plus you don't need to deal w/cross-db joins when you're trying to lookup user information.
Update: In response to your update... One of the advantages to each customer having their own DB is also the ability to restore a customer if they really need it. If you've split the customer's data into two databases how do you restore it? Also, again, you'll need to worry about cross-db data access if the users are defined in a DB other than the home DB.
I've always been of the opinion that security should be enforced at the application level, not the database level. With that said, I see no problem with your intended approach. Managing accounts and roles through a central database makes the application more maintainable in the long run.
You may want to look into using the ASP.NET membership provider for handling the authentication plumbing. That would work with your stated approach and you can still keep all of the authentication data in a separate database. However, I agree with Chris that keeping one DB will utlimately be more maintainable.
Is it better to extend my business database with the tables of the ASP.NET Membership Security model. Or should I have a different datastore where I only manage Identities and Roles... Basically 1 or 2 databases?
This can depend on scale. If it's an enterprise solution with different apps sharing one membership source the answer is simple - separate them. There might also be performance reasons why you would want to separate this data from the rest of the app. Arguably these tables do not belong in a data warehouse for example.
The only thing the 2 databases solution doesn't give you is referential integrity. If you extend your membership tables to hold more application specific details about the user, and these tables need to link into the main database then you might want to keep them together. Otherwise you would need some sort of replication job maintaining this for you.
This is quite subjective, but unless those users are going to be using more than one database, then I'd say keep them in the same db.
I would only use a separate database for users and roles if those users and roles were used in more than one database.
So no, I'd never use two. I might however use three.
Which database platform are you using? If one that supports schemas within a database, e.g. SQL Server 2008, then you can put your membership tables into their own schema, for neatness. You can also add cross-schema foreign keys if required.