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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...
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...
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...
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...
A SQL Injection attack and search engines
A few weeks after my previous posting of a SQL Injection Advisory link, a new SQL Injection attack came up. Here's a post describing it; it also includes other useful links: http://www.rtraction.com/blog/devit/sql-injection-hack-using-cast.html A search Read More...
New Microsoft Security Advisory on SQL Injection
This came up yesterday: http://www.microsoft.com/technet/security/advisory/954462.mspx . It has good information and links. Read More...
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...
SQL Server: Password policy FAQ
I am starting this post to collect frequent Q&A related to password policy. I plan to keep updating the post if anything new is worth adding to it. Note that this FAQ does not cover SQL Server Compact Edition. Also note that BOL stands for Books OnLine. Read More...
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...
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...
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...
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...
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...
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...
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...
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