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Finding information about which account xp_cmdshell is running as
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, Read More...
Posted 27 October 09 02:24 by lcris | 0 Comments   
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SQL Injection watch blog
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. Read More...
Posted 14 August 09 02:34 by lcris | 0 Comments   
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Basic SQL Server Security concepts: ownership, CONTROL, TAKE OWNERSHIP
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 Read More...
Posted 11 August 09 03:39 by lcris | 0 Comments   
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SQL Server: Windows Groups, default schemas, and other properties
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 Read More...
Posted 22 August 08 04:15 by lcris | 0 Comments   
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SQL Server 2005: How to debug login failures (18456, anyone?)
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 Read More...
Posted 21 February 08 04:05 by lcris | 0 Comments   
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SQL Server undocumented password hashing builtins: pwdcompare and pwdencrypt
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 Read More...
Posted 31 October 07 11:08 by lcris | 0 Comments   
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Basic SQL Server Security concepts: SIDs, orphaned users, and loginless users
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 Read More...
Posted 25 October 07 05:42 by lcris | 0 Comments   
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Security and copy protection
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 Read More...
Posted 24 September 07 03:57 by lcris | 0 Comments   
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Basic SQL Server Security concepts - ownership chaining: good and evil; schemas
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, Read More...
Posted 13 September 07 11:37 by lcris | 0 Comments   
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Basic SQL Server Security concepts - permissions and special principals: sa, dbo, guest
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 Read More...
Posted 12 September 07 03:12 by lcris | 0 Comments   
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SQL Server 2005: About login password hashes
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 Read More...
Posted 30 April 07 09:22 by lcris | 1 Comments   
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Basic SQL Server Security concepts - logins, users, and principals
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 Read More...
Posted 23 March 07 10:25 by lcris | 2 Comments   
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SQL Server 2005 security presentations at PASS - Pre Conference
If you missed the PASS Pre Conference security presentations, you can now catch up by viewing them online: http://cmcgc.com/Media/WMP/261115/ . Read More...
Posted 08 December 06 08:49 by lcris | 0 Comments   
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Who needs encryption?
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 Read More...
Posted 30 November 06 06:07 by lcris | 4 Comments   
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SQL Server 2005: Demo for enabling database impersonation for cross database access
There is an excellent article on this topic in Books Online: Extending Database Impersonation by Using Execute As . I just wrote a small demo to illustrate the techniques described in that article. It can be used as a companion to that article, if you're Read More...
Posted 24 October 06 07:23 by lcris | 0 Comments   
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