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From Jonathan Mischo <>
Subject Re: bandwidth limiting Cassandra's replication and access control
Date Thu, 12 Nov 2009 00:53:46 GMT
Let me put this in a slightly different (and probably fairly tactless)  
context here, for those of us without an infosec background.

1) Per-keyspace authentication allows for accountability and access  
control, at least at a rudimentary level.  Without this, there are  
several types of applications that it would be impossible to use  
Cassandra for, due to data security restrictions.  Not just  
impractical, but probably illegal in some cases.

2) If you have an intrusion into your network or a malicious user  
internally (yes, this happens), you're completely unprotected without  
per-keyspace authentication.

3) Per-keyspace authentication is done once-per-session; if you use  
connection pooling or persistent connections of any sort in your  
application, this has virtually zero overhead.

4) It's REALLY bad infosec practice to have your data accessible by  
anyone, anytime, with no restrictions, which is how Cassandra  
currently operates.  While good network and application security can  
minimize the risks, at present, a typo or missed change in a cut and  
paste can potentially damage your data, especially if you have CFs/ 
SCFs that have the same name in two keyspaces.

5) This is common practice, pretty much everywhere.  Every SQL  
database, and almost every NOSQL database employs some form of AAA  
(Authentication, Authorization, and Accountability) functionality.   
It's pretty much an expected feature, though the granularity varies  
depending on the implementation.  AAA isn't expensive, but it sure can  
save your butt later (and/or help you prosecute that Evil Nasty  
Person).  It can also provide you with nifty "Unauthorized" exceptions  
that let you know you forgot to change the keyspace in your  
configuration and almost did a Really Bad Thing.

6) Your bosses will like it (and you) a lot better if they don't have  
to ask you where your organization's data went.

Hope this helps drive the point home that authentication and  
authorization (as proposed) has near-zero overhead and is actually  
pretty bad (read: slightly horrifying to auditors and security people,  
but really exciting for evil people and typo gremlins) to not have.


On Nov 11, 2009, at 4:18 PM, Coe, Robin wrote:

> Do you mean that users interacting with Cassandra through the CLI  
> should be restricted based on a security service?  I agree.   
> However, I believe the more common case is to front the Cassandra  
> service with an application layer, as you would expose a relational  
> backend.  For that kind of service, the application should control  
> the security.
> Basically, a user request to Cassandra is not stateful; any request  
> should be able to perform a transaction against any node in the  
> cluster, using an appropriate consistency model for the request.   
> Requiring something like real time token synchronization across all  
> nodes in a cluster seems outside of Cassandra’s  eventual  
> consistency model.
> Securing the data is intrinsically application-specific.  While I  
> could see adding a plugin that makes the CLI access point secured, I  
> would still want that to be made in a pluggable fashion, so it could  
> be swapped out with a custom implementation.
> Of course, this is just my point of view, but I make it after having  
> written several security layers on J2EE apps over the years and none  
> of them have been the same.  Besides that, I want the data layer to  
> be highly efficient and in my opinion, it isn’t the work of the data  
> service to impose security.
> Robin.
> From: Brandon Williams []
> Sent: November 11, 2009 4:44 PM
> To:
> Subject: Re: Re: bandwidth limiting Cassandra's replication and  
> access control
> On Wed, Nov 11, 2009 at 9:40 AM, Coe, Robin <>  
> wrote:
> IMO, auth services should be left to the application layer that  
> interfaces to Cassandra and not built into Cassandra.  In the  
> tutorial snippet included below, the access being granted is at the  
> codebase level, not the transaction level.  Since users of Cassandra  
> will generally be fronted by a service layer, the java security  
> manager isn’t going to suffice.  What this snippet could do, though,  
> and may be the rationale for the request, is to ensure that  
> unauthorized users cannot instantiate a new Cassandra server.   
> However, if a user has physical access to the machine on which  
> Cassandra is installed, they could easily bypass that layer of  
> security.
> What if Cassandra IS the application you're exposing?  Imagine a  
> large company that creates one large internal Cassandra deployment,  
> and has multiple departments it wants  to create separate keyspaces  
> for.  You can do that now, but there's nothing except a gentlemen's  
> agreement to prevent one department from trashing another  
> department's keyspace, and accidents do happen. You can front the  
> service with some kind of application layer, but then you have  
> another API to maintain, and you'll lose some performance this way.
> -Brandon

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