Our aim is to implement the principle of least privilege with a defense in depth approach. In this particular case, this means that a query sent by an unprivileged user should not have admin rights on the database side. RDBMS such as PostgreSQL provide very powerful, expressive and well-tested access control mechanisms : RBAC, row-level security, parametrized views, etc. These controls, indeed, are usually totally ignored in web applications which use the paradigm "1 application == 1 user", this user has thus admin role. But heavy clients often use several different users on the database side (either one per final user or one per specific role) and thus benefit from the access control of the database.
Access control from the DB is an addition to access control in the web application. AC in the webapp will be more precise but may probably suffer from some bugs ; AC in the DB will be a bit more laxist but better enforced, limiting damages in case of an application bug.
So in our case, we want to create a DB user for every application user. Then, the connection to the database belongs to this specific user and the database can thus enforce that a simple user cannot execute admin operations. An intermediate possibility would be to drop some privileges before executing a query, but our preferred way is to connect to the database as the currently logged-in user. The login-password is sent by the user when he authenticates and we just pass it to the DBMS. Scalability is not (yet) an issue for our application, we can sacrifice some scalability for this type of security.
Would you have any hints to help us achieve this ?
I'm trying to get some advice on how to approach a security architecture on Azure.
Background:
We are looking at building a multi-tenant app on Azure that needs to be extremely secure (personally sensitive data). The app will be accessed by standard browsers and mobile devices.
Security access types:
We have three types of users / access types...
1 - plain old user/password over https is fine, accessing both general, non private SQL plus hosted files
2 - user/pass over https, but need authentication of users via certificates that will be installed on user machines/devices. This level of user will need access to sensitive data which should be encrypted at rest both in database, and also any uploaded files.
3 - same as (2) but with the addition of some two factor authentication (we have used YubiKey for other things - might look towards a phone OTP offering as well)
Most users will only have access to their own tenant databases, however we have "account manager" type users that need access to selected tenant data, therefore we expect that they will need either a copy of one certificate per tenant they serve, or we will have to use some kind of master certificate.
Database type:
From a multi-tenant point of view it seems Azure Federated SQL is a good way to go because (a) we simply write one app with "TenentID" key in each table, and after login, set a global filter that handles the isolate for us (b) we understand that Azure federated SQL actually in the background maintains separate SQL database instances per tenant.(Ref: http://msmvps.com/blogs/nunogodinho/archive/2012/08/11/tips-amp-tricks-to-build-multi-tenant-databases-with-sql-databases.aspx)
Can anyone point to any links or give advice in relation to the approach needed to setup and manage file shares, encryption of SQL and file data at rest, authentication of users etc. (automated management on new user signup pref).
I can't really help on the certificates, but you will indeed need some "master certificate". If you are planning on using Azure website, you can't use your own certificates currently.
Concerning the database setup. SAAS applications build on trust, so you NEVER (EVER) want to be showing or editing the data of using to other users.
Therefore I strongly suggest that you don't use the TenantID for each table. This would leave still the possiblity of an attack by a malicious user or an error by some developer.
The only way to get around these risks are
extensive testing
physical different tables to store each tenant data.
Personally I believe that even with very extensive+automated testing you can't have 100% code coverage against malicious users. I guess I am not alone.
The only way out IMHO is physical different tables. Let's look at the options:
different server: valid, but pretty expensive in azure
different database: valid, less management overhead but same objection as the previous option - expensive if you have a lot of tenants
different schema's: the solution. Think about it...
you only have to manage users and there default schema's
you can back-up schema's using powershell
you can move schema's to other databases with some work
You can still digg into SQL federation if you need to.
the major drawback is that you will need to support database upgrades for each tenant.
Have you read on azure.com any articles about multi-tenancy? http://msdn.microsoft.com/en-us/library/windowsazure/hh689716.aspx
i'm planning to use a combination of entity framework + plain sql access for a large sized project that i'm about to start. its an ASP.NET web application.
for auditing data, i was thinking of creating a user in sql db for every user in membership that i create so that the auditing can automatically track the asp.net logged in user activities. so basically, if i could impersonate as that username for the connection that is used, then sql server will automatically log.
do you know how to implement this in entity framework, i'm fairly new to ef.
if this is not possible, do you know another solution WITHOUT manually including userid in every sql insert/update/delete.
thanks..
That is pretty bad idea. If you want this kind of auditing don't use membership and instead use Windows accounts directly with Kerberos delegation as common in large ERP or CRM systems = each user will have access to the database with his own domain account but it requires very correctly specifying security for the database and it will most probably lead to design without entity framework because you will not want users to be albe to execute queries directly but only to execute stored procedures under their user context.
If your application should be publicly available then this level of auditing is not for you and you must roll your own solution on the application level (not the database level).
We have a system with 2 clients (which will increase). These two clients connect to the same server/database, however neither should be able to see the others sensitive information. There is however some shared non sensitive information.
There is also an administrative department who does work on behalf on both of the clients. They are allowed to see all sensitive data.
We currently handle this by holding a ClientID against the tables in question and with a mixture of views and queries check against the ClientID to control access for each client.
I want to move to a consistent handling of this in our system e.g. all views, or all queries, however I just wondered if there was perhaps an easier/ better Pattern than using views to handle this situation?
We're using Sql Server 2005 however upgrade to 2008 is possible.
Cheers
the most logical way is to have (indexed) views filtered by what each user can see.
add read/write permisisons to each client for their views. admins access the tables directly.
but it looks to me that each client is a logicaly separated entity form the others.
if that's the case you might consider having 1 db per client and 1 db for shared stuff.
admins can access everything, each client cas only access it's own db and read from common db.
a 3rd option is to look into schemas and separate your clients there.
I know that LDAP is used to provide some information and to help facilitate authorization.
But what are the other usages of LDAP?
I will focus on why using LDAP, not what is LDAP.
The use model is similar like how people use library cards or phonebooks. When you have a task that requires “write/update once, read/query many times”, you might consider using LDAP. LDAP is designed to provide extremely fast read/query performance for a large scale of dataset. Typically you want to store only a small piece of information for each entry. The add/delete/update performance is relatively slower compared with read/query because the assumption is that you don’t do “update” that often.
Imagine you have a website that has a million registered users with thousands of page requests per second. Without LDAP, every time users click a page, even for static page viewing, you will probably need to interact with your database to validate the user ID and its digital signature for this login session. Obviously, the query to your database for user-validation will become your bottleneck. By using LDAP, you can easily offload the user validation and gain significant performance improvement. Essentially, in this example, LDAP is another optimization layer outside your database to enhance performance, not replacing any database functions.
LDAP is not just for user validation, any task that has the following properties might be a good use case for LDAP:
You need to locate ONE piece of data many times and you want it fast
You don’t care about the logic and relations between different data
You don’t update, add, or delete the data very often
The size of each data entry is small
You don’t mind having all these small pieces of data at a centralized place
That's a rather large question.
LDAP is a protocol for accessing a directory. A directory contains objects; generally those related to users, groups, computers, printers and so on; company structure information (although frankly you can extend it and store anything in there).
LDAP gives you query methods to add, update and remove objects within a directory (and a bunch more, but those are the central ones).
What LDAP does not do is provide a database; a database provides LDAP access to itself, not the other way around. It is much more than signup.
Well, there are LDAP servers and the LDAP protocol. Combined, it's a data store, or a database. It's not relational, but it's just a place to store data, and it's optimized to be efficient at reads more than writes. It doesn't support transactions.
Now, it happens to be very popular for storing credentials, but that's by no means its only purpose, and not its original purpose.
LDAP stands for Lightweight Directory Access Protocol. As the name suggests, it is a lightweight protocol for accessing directory services, specifically X.500-based directory services. LDAP runs over TCP/IP or other connection oriented transfer services. The nitty-gritty details of LDAP are defined in RFC2251 "The Lightweight Directory Access Protocol (v3)" and other documents comprising the technical specification RFC3377. This section gives an overview of LDAP from a user's perspective.
What kind of information can be stored in the directory? The LDAP information model is based on entries. An entry is a collection of attributes that has a globally-unique Distinguished Name (DN). The DN is used to refer to the entry unambiguously. Each of the entry's attributes has a type and one or more values. The types are typically mnemonic strings, like cn for common name, or mail for email address. The syntax of values depend on the attribute type. For example, a cn attribute might contain the value Babs Jensen. A mail attribute might contain the value babs#example.com. A jpegPhoto attribute would contain a photograph in the JPEG (binary) format.
How is the information arranged? In LDAP, directory entries are arranged in a hierarchical tree-like structure.
LDAP is the Lightweight Directory Access Protocol. Basically, it's a protocol used to access data from a database (or other source) and it's mostly suited for large numbers of queries and minimal updates (the sort of thing you would use for login information for example).
LDAP doesn't itself provide a database, just a means to query data in the database.
The main idea of LDAP is to keep in one place all the information of a user (contact details, login, password, permissions), so that it is easier to maintain by network administrators. For example you can:
use the same login/passwd to login on an Intranet and on your local computer.
give specific permissions to a group of user. For example some could access some specific page of your Intranet, or some specific directories on a shared drive.
get all the contact details of the people in a company on Outlook for example.
The main benefit of using LDAP is that information for an entire organization can be consolidated into a central repository. For example, rather than managing user lists for each group within an organization, LDAP can be used as a central directory accessible from anywhere on the network. And because LDAP supports Secure Sockets Layer (SSL) and Transport Layer Security (TLS), sensitive data can be protected from prying eyes.
LDAP also supports a number of back-end databases in which to store directories. This allows administrators the flexibility to deploy the database best suited for the type of information the server is to disseminate. Because LDAP also has a well-defined client Application Programming Interface (API), the number of LDAP-enabled applications are numerous and increasing in quantity and quality.
LDAP main usage is to provider faster retrieval of data . It acts as a central repository for storing user details that can be accessed by various application at same time .
The data that is read various time but we rarely update the data then LDAP is better option as it is faster to read in it because of its structure but updating(add/updatee or delete) is bit tedious job in case of LDAP
Security provided by LDAP : LDAP can work with SSL & TLS and thus can be used for sensitive information .
LDAP also can work with number of database providing greater flexibility to choose database best suited for our environment
Can be a better option for synchronising information between master and its replicase
LDAP apart from supporting the data recovery capability .Also , allows us to export data into LDIF file that can be read by various software available in the market
I have had the opportunity to start a project for school about ldap, from scratch, but before getting to know what is ldap, I had to understand what is a directory, there are many (most used directories are novell and windows), here you can see what the directory in Wikipedia.
And ldap is the protocol to communicate with the board, one of the best books I've found is this one.
LDAP is just a protocol to access structured information. LDAP has standardized local and remote access to information whereas in case of database there is only standardized local access and remote access is proprietary.
LDAP server is optimized for search operation and database for transactions(Insert/Delete).
For more information refer following link:
http://www.itszero.in/2013/09/what-is-ldap-ad-adam.html
In Windows Server LDAP is a protocol which is used for access Active Directory object, user authentication, authorization.
To take the definitions the other mentioned earlier a bit further, how about this perspective...
LDAP is Lightweight Directory Access Protocol. DAP, is an X.500 notion, and in X.500 is VERY heavy weight! (It sort of requires a full 7 layer ISO network stack, which basically only IBM's SNA protocol ever realistically implemented).
There are many other approaches to DAP. Novell has one called NDAP (NCP Novell Core Protocols are the transport, and NDAP is how it reads the directory).
LDAP is just a very lightweight DAP, as the name suggests.
Well,
LDAP is a protocol(way) to access structured info. LDAP uses client-server model so, LDAP client makes request to access required info. LDAP server stores info not in relational way but in attribute and value pair. You can use LDAP to assign same privilege to group of user or same credential to access multiple services. For more details refer following link : http://www.zytrax.com/books/ldap/ch2/
LDAP stands for Lightweight Directory Access Protocol.It is used in Active Directory for communicating user queries..e.g.. LDAP can be used by users to search and locate a particular object like a laser printer in a domain.
LDAP is also used to store your credentials in a network security system and retrieve it with your password and decrypted key giving you access to the services.
Light weight directory access protocal is used to authenticate users to access AD information
LDAP stands for Lightweight Directory Access Protocol (not a database). As the name says it is used for accessing/reading data. LDAP is a protocol to access data from directory servers which is a hierarchical database, it is designed for reading, browsing, searching, and organizing data. This kind of data we do not modify regularly or it is very infrequently modified data.
Big companies store their internal data, for example, user names with their title and id or phonebooks of their workers on LDAP servers (this server implements a tree-structured database). Those data can be reached by the workers of that company through the LDAP protocol. LDAP protocol runs over TCP or UDP protocol and accesses the server through port 389. There is also LDAPS that runs over SSL and accesses the server through port 636.