If you’re using the CustomAttributeData APIs to examine declarative security permission, you might notice that the returned information looks a little strange.  The CustomAttributeData object that you’ll see for the declarative security attribute...

With all the changes in the security system of .NET 4, the question frequently arises “so, is CAS dead now?”. One of the reasons that this question comes up so frequently, is that the term CAS in the .NET 1 security model was overloaded to refer to many...

SecAnnotate (available in the final .NET 4 SDK, and in beta form here ) can be used to analyze your assemblies, especially APTCA assemblies in order to find transparency violations without needing code coverage from a test case. Instead, the static analysis...

One of the design goals of the security transparency system in the CLR is that it should be as static as possible and not rely on dynamic state (such as the call stack) to function. A fallout of this is that we can write tools to analyze assemblies and...

In my last post I talked about the two different security rule sets supported by the v4 CLR .  At a high level, level 1 is the v2.0 security transparency model, and level 2 encompasses the updated v4 security transparency model.  Digging down...

Earlier this week, we looked at how the v4 CLR continued the evolution of the security transparency model that started in v2 and started evolving with Silverlight in order to make it the primary security enforcement mechanism of the .NET 4 runtime. The...

Now that we know the basics of security transparency , let's look at how it evolved over time. In .NET v2.0, many of the transparency rules we previously looked at were in place , with the exception of some of the inheritance rules that were introduced...

Last time we looked at the set of operations that can only be performed by security critical code . One interesting observation is that just because you are doing one of these operations does not mean that your method in and of itself is security sensitive...

One of the biggest changes in the .NET 4 security model is a move toward security transparency as a primary security enforcement mechanism of the platform. As you'll recall, we introduced security transparency in the v2 release of .NET as more of an audit...

Over the last few weeks we’ve been taking a look at the updates to the CLR security policy system in the v4 release of the .NET Framework. Here’s a quick index of those topics: Overview Security Policy in the v4 CLR Sandboxing in .NET 4...

Over the last few weeks we’ve been looking at the changes to security policy in .NET 4, namely that security policy is now in the hands of the host and the operating system. While we’ve looked at how to update code that implicitly uses CAS policy , loads...

Over the last few posts, I’ve been looking at how the update to the CLR v4 security policy interacts with how you write managed code against the v4 .NET Framework.  So far we’ve looked at the implicit uses of CAS policy, such as loading assemblies...

In my last post about changes to the CLR v4 security policy model, I looked at APIs which implicitly use CAS policy in their operation (such as Assembly.Load overloads that take an Evidence parameter), and how to migrate code that was using those APIs...

A while back I did an interview with Charles Torre   about the changes to security in CLR v4, and he posted it to the Channel 9 videos site yesterday. I start out talking about the security policy changes I've been covering here over the last week...

Kris Makey, who works on the Visual Studio team, has written up a good blog post about the changes you’ll see on the security tab in Visual Studio 10 when it comes to editing permission sets .  He covers what the changes are, and some of the reasons...

Last week we looked at sandboxing and the v4 CLR – with the key change being that the CLR now defers exclusively to the host application when setting up sandboxed domains by moving away from the old CAS policy model, and moving instead to simple sandboxed...

Yesterday I talked about the changes in security policy for managed applications , namely that managed applications will run with full trust - the same as native applications - when you execute them directly. That change doesn’t mean that managed code...

One of the first changes that you might see to security in the v4 CLR is that we’ve overhauled the security policy system.  In previous releases of the .NET Framework, CAS policy applied to all assemblies loaded into an application (except for in...

The first beta of the v4.0 .NET Framework is now available , and with it comes a lot of changes to the CLR's security system. We've updated both the policy and enforcement portions of the runtime in a lot of ways that I'm pretty excited to finally see...

Over the last week, we've made a couple of updates to our Codeplex projects to add authenticated symmetric encryption to the managed cryptography surface area for the first time. Since we've never supported authenticated symmetric algorithms in managed...

Reid Borsuk, an SDE/T on the CLR security team, has released a fully transparent implementation of the MD5 hash algorithm to the MSDN Code Gallery .  Since the code is entirely transparent, it can be used as part of a Silverlight application that...

The crypto config schema has been a bit of a hot topic around here lately, specifically around how to modify the CLR's machine.config to get custom crypto types registered with CryptoConfig. Let's take a quick look at what CryptoConfig is first, and then...

Earlier this month, we released .NET 3.5 SP 1 .  One of the new features available in this update is that RSACryptoServiceProvider has gained the ability to create and verify RSA-SHA256 signatures. Since RSACryptoServiceProvider relies on the underlying...

The CLR Security Team just launched our CodePlex site: http://www.codeplex.com/clrsecurity .  Currently, it contains two assemblies that provide additional functionality to the security APIs shipped in v3.5 of the .NET Framework. We'd love your feedback...

Dino Esposito has an article in the March Dr. Dobb's Journal taking a look at the Silverlight platform from a security perspective: The Silverlight 2.0 Security Model .  The second half in particular boils down some of the details of the transparency...