This post is based on an old presentation I gave several years back. A video of the presentation used to be available here , but today I couldn't get it to work, so I am attempting to make available most of the information from the presentation within...

If you ever needed to debug a permission related issue when using xp_cmdshell, you have probably realized that a crucial piece of information is about what particular account xp_cmdshell is executing under. If you are the administrator of the database...

I was looking for information on a new SQL injection attack when I stumbled upon this very useful blog: http://s3cwatch.wordpress.com/ . It's worth a look from time to time, to get an idea of what attacks are going on in the wild.

I realized today that while I have discussed earlier object permissions , I have not gone into the details of object ownership. I want to cover the following here: ownership of objects, how it can be changed, and the relatively new permission CONTROL...

Exceptions are dangerous because people like to simplify their thinking process using rules, so exceptions always carry the risk of being overlooked. In security, exceptions are a bad thing because they make the model more complex and complex systems...

In my series of new posts on old topics, I decided to gather today several pieces of information that I think will help in debugging SQL Server login failures. Although most information should remain useful for future versions as well, some of it may...

I want to address the topic of requesting feature changes in Microsoft products, to point to some tools that can help, and to describe ways to use those tools more effectively. This post is based on my experience working on customer requests while being...

Encryption builtin functions in SQL Server have no known issues and, if used properly, they will produce the expected results. However, if they are used incorrectly, it can be hard to figure out what exactly is the problem, so in this post I am going...

Aaron Morton has a very interesting post and demo that show how MARS can be used to access keys temporarily opened by a procedure. This is a must-read for anyone that is interested in implementing custom restrictions around the use of encryption keys...

I often recommended to only encrypt data in SQL Server using symmetric keys and to reserve the use of asymmetric encryption for protection of symmetric keys and for signing. In this post, I will go in more detail about why asymmetric encryption is not...

This issue has been addressed before on forums, but with the heavy traffic, it can be hard to find the proper post. So, I'll provide some explanations here as well. Note: This article is written with symmetric encryption in mind, but the actual technique...

I have addressed this topic in previous threads and comments ( here , here , and here , for example), both on this blog and on various forums, but it looks like when you need the answer, it can be hard to dig out. So I'm hoping that by placing these steps...

I wrote earlier today a reply on this topic on the public forums, but now that I checked, the reply appears to have got lost, although I still entertain the hope it may only have got delayed and will appear there in 24 hours. Anyway, this is the reason...

First, I must say that I don't know why these exist in an undocumented form. They have been around for a long time and a search on their names gets me back pages of hits. Being undocumented means that their actual implementation may change slightly from...

I am grouping here two topics (orphaned users and loginless users) that are actually very different, but I have often seen confusion between them, so I am covering them together in an attempt to dispel that confusion. In a previous discussion of logins...

To avoid any confusion, this post is not about the use of certificates for securing the communication between a client machine and the server; instead, this refers to the use of certificates created via the CREATE CERTIFICATE DDL. I am prompted in...

I have kept silent on this feature while it was being developed, but as it has now been publicly advertised in various ways (being mentioned here , here , here , and here , for example), I think it is probably time to write a bit about it. Given that...

I have been watching the SQL Server Security forum for several years now and there is one question that gets spawned about once a month under different titles. It invariably begins with a request for guidance on how to secure access to a database, which...

At some point during SQL Server's history, its designers must have confronted the following problem: how to give someone permission to see parts of a table without giving him any permission on the table? Slices of a table are easily defined using views...

In a previous post , I talked about the various types of principals in SQL Server. Let's have a further look in this post at permissions and at some of the hardcoded principals that ship with any installation of SQL Server. Permissions are what allow...

There seem to be a couple of misconceptions around the SQL Server handling of login passwords. Hopefully, by the end of this post, you will have a much clearer idea about what is going on under the covers. Note that this refers to the passwords of logins...

In this post I'd like to talk about some basic SQL Server security concepts. SQL Server has a less common design that can confuse users familiar with the security features of other software products, such as Microsoft Windows OS; in particular, the difference...

Buck Woody just wrote an interesting post about the process of writing documentation for SQL Server. After reading this, you should have no excuse for not providing feedback on Books Online articles that you feel are incomplete or have inaccurate information...

If you missed the PASS Pre Conference security presentations, you can now catch up by viewing them online: http://cmcgc.com/Media/WMP/261115/ . [UPDATE 8/24/2010] : The main content of my execution context presentation is available here . The associated...

For those that read my previous posts, the question in the title may be startling. I want to reassure you from the start: this post is not about encryption being a useless technique; it is just about it not being a solution for certain problems and definitely...