Dan Sellers's WebLog : OnLine Events

SQL Server 2005 Security for Developers Webcast for on-demand viewing is available

dansellers — Fri, 24 Mar 2006 09:26:00 GMT

The on-demand Webcast of SQL Server 2005 for Developers, conducted on March 22, 2006, by Rob Walters--Program Manager, SQL Server Security--and I, is now available for on-demand viewing.

Post Notes from this Webcast can be found at my blog.

Look forward to seeing everyone for next week webcast.

Post Webcast’s Notes: Securing SQL Server 2005 for Developers

dansellers — Wed, 22 Mar 2006 22:59:00 GMT

This morning was a jammed filled session covering off a lot of changes made to Microsoft SQL Server 2005. Over the last few weeks we talk exclusively about Front End security issues such as Input trust and the creation of a Development and Design environment to better emulate your production environment. However, today we switched gears by examining the security enhancements made to SQL Server 2005.

A good place to start the talk on was with the Surface Configuration Tool. By default many features including xp_cmdshell, clr and even remote connections have been turned off in SQL Server 2005. Therefore, if you were to immediately start developing in SQL Server 2005 you might start experiences security errors when invoking some of these features. Thus, the Surface Configuration Tool is an excellent way to examine which features are disabled and also provides the ability to enable the particular features required. The SQL Server Surface Area Configuration tool is located under All Programs, Microsoft SQL Server 2005, Configuration Tools.

Authentication has changed in SQL Server 2005 with the support of Windows Password Policies enforcements when creating SQL Server login accounts. This is an excellent way to enforce strong passwords and an expiration policy on passwords depending upon your security needs. This can be configured on a per-login basis as demonstrated with the script below:

create login foo with password='@#Hkjsdf#$#VDSVSQ@!',

CHECK_EXPIRATION=ON,CHECK_POLICY=ON

select * from sys.sql_logins

declare @name nchar(100)

SET @name ='foo'

SELECT LOGINPROPERTY( @name, 'PasswordLastSetTime' ) AS PasswordLastSetTime,

LOGINPROPERTY( @name, 'IsExpired' ) AS IsExpiried,

LOGINPROPERTY( @name, 'IsLocked' ) AS IsLocked,

LOGINPROPERTY( @name, 'IsMustChange' ) AS IsMustChange,

LOGINPROPERTY( @name, 'LockoutTime' ) AS LockoutTime,

LOGINPROPERTY( @name, 'BadPasswordCount' ) AS BadPasswordCount,

LOGINPROPERTY( @name, 'BadPasswordTime' ) AS BadPasswordTime,

LOGINPROPERTY( @name, 'HistoryLength' ) AS HistoryLength,

LOGINPROPERTY( @name, 'PasswordHash' ) AS PasswordHash

--cleanup

drop login foo

Schemas have been added as an abstract between the database and the owner of the objects. Therfore, by assigning objects to schema it is possible to drop users without rewriting your applications as the name resolution is no longer depend upon the user or principals names. We can continue to use the default schema of dbo similar to what we are used to in SQL Server 2000. However, if your application creates objects in the database and you want those objects to be created under the dbo schema then you must grant your application dbo privileges when connecting to the database. This will increase the attack surface of your application as well increasing the severity if your application is vulnerably to SQL Injection attacks. Schemas are also a nice mechanism to scope your permissions. For example, you can grant select permission on a schema. This will grant select permission to all the tables in that schema alone but not the other tables in other schemas.

Execute Content provides an excellent mechanism to have your modules such as functions, proc and triggers to run under a different user context then the caller of the module. The permissions that one can assign in SQL Server 2005 is very granular especially compared with SQL Server 2000, however, if you are unable to provide a single permission attribute to some database users then you can use execute content. Therefore, the proc can run under a privilege account that has certain permission such as truncate table, and the caller only has to be granted execute permission on the proc itself and not truncate table. Highlighted in the demo script below:

--This example will create 3 users

-- User1 will have a table MyTable

-- User2 will have a stored proc that select's the table

-- User3 will have execute permissions on User 2's stored proc

--This demo show the use of EXECUTE AS functionality

--Create our users

create login Login1 with password='(*&sdf87786sdf'

create login Login2 with password='(*&sdf87786sdf'

create login Login3 with password='(*&sdf87786sdf'

create database ExampleDB

use ExampleDB

--User 1 will have a table

create user User1 for login Login1 with default_schema=User1

create schema User1 authorization User1

--User 2 will have SELECT access and write a proc to access

create user User2 for login Login2 with default_schema=User2

create schema User2 authorization User2

--User 3 will have the right to exec the proc

create user User3 for login Login3 with default_schema=User3

create schema User3 authorization User3

grant create table to User1

grant create proc to User2

execute as login='Login1'

create table User1.MyTable

(ANumber int)

insert into MyTable values (1)

insert into MyTable values (2)

insert into MyTable values (3)

grant select on MyTable to User2

revert

execute as login='Login2'

--create a stored proc that will return the rows in our table

create proc ViewMyNumbers

BEGIN

select * from User1.MyTable

END

grant execute on ViewMyNumbers to User3

revert

execute as login='Login3'

--Can't access table directly

select * from User1.MyTable

--I can't execute the proc since I don't have permissions on the unlying table

exec User2.ViewMyNumbers

--What I can do is alter the proc and set it to "execute as owner"

revert

execute as login='Login2'

ALTER PROCEDURE ViewMyNumbers

WITH EXECUTE AS OWNER

BEGIN

select * from User1.MyTable

END

revert

execute as login='Login3'

--Still can't access table directly

select * from User1.MyTable

--Now I can access it and I didn't have to give User1

--any permissions on MyTable

exec User2.ViewMyNumbers

revert

SQL Server now provides build DDL statements and functions for encrypting and decrypting data inside the database and not necessary in manage code anymore. Encryption has never really been difficult but rather the management of the keys becomes the overwhelming issue. Therefore, SQL Server 2005 supports key management solution including the ability to manage the protection of the keys through a password that must be supplied by an application or an user. Or the protection of all keys in a database can be rooted under the Database Master key which is protected by default of the Service Master Key using the DPAPI for the instance of the SQL Server. I would highly recommend that you visit this excellent blog on certificates and Keys in SQL Server 2005. Demo script is provided below:

--Encrypt content demo

USE Master

--Create Database, Users, Schemas, Table Object--

Create Database AccountsDB

Use AccountsDB

--create two logins that will be used

--logins for two consultants in a investors office

Create login Sheila with password='Capucci4!'

Create login Jon with password='Capucci4!'

--create users with Default schema

Create user Sheila with DEFAULT_SCHEMA=Fin

Create User Jon with DEFAULT_SCHEMA=Fin

Create SCHEMA Fin Authorization Sheila

--Create Table to client table

Create table Fin.Clients (Id int, clientname nvarchar(30),

investor varchar(20),

SIN varbinary(100), Portfolio varbinary(100))

--Assign permission to table

grant select, insert on Fin.Clients to Sheila

grant select, insert on Fin.Clients to Jon

--Now create a certificate for each consultant

Create certificate SheilaCert

authorization Sheila with subject='SheilaCert'

--Notice error, we need to create a database master key first

CREATE MASTER KEY ENCRYPTION BY PASSWORD ='Capucci4!'

--Now lets create the certificates

Create certificate SheilaCert

Authorization Sheila with subject = 'SheilaCert'

Create Certificate JonCert

Authorization Jon with subject = 'JonCert'

--create symmetric keys for each of the consultants

CREATE SYMMETRIC KEY SheilaKey AUTHORIZATION Sheila

WITH ALGORITHM = TRIPLE_DES

ENCRYPTION BY CERTIFICATE SheilaCert;

CREATE SYMMETRIC KEY JonKey AUTHORIZATION JON

WITH ALGORITHM = TRIPLE_DES

ENCRYPTION BY CERTIFICATE JonCert;

--View the list of the keys in the database

Select * from sys.symmetric_keys

--SIMULATE CONNECTING AS SHEILA--

--Login and Insert Client Data--

Execute As login='Sheila'

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

--open your symmetric key for usage

OPEN SYMMETRIC KEY SheilaKey

DECRYPTION BY CERTIFICATE SheilaCert;

--use the key to insert investor's client records

--including encrypted values into the table

insert into Fin.Clients values (1,'Neo','Sheila',

encryptByKey(Key_GUID('SheilaKey'),'111-111-111'),

encryptByKey(Key_GUID('SheilaKey'),'$150,000,000'))

insert into Fin.Clients values (2,'Smith','Sheila',

encryptByKey(Key_GUID('SheilaKey'),'222-222-222'),

encryptByKey(Key_GUID('SheilaKey'),'$200,000'))

--close all open keys

close all symmetric keys

--logging out of sheila's context

REVERT

--SIMULATE CONNECTING AS JON--

execute as login ='Jon'

--open your symmetric key for usage

OPEN SYMMETRIC KEY JonKey

DECRYPTION BY CERTIFICATE JonCert;

insert into Fin.Clients values (3,'WhiteRabbit','Jon',

encryptByKey(Key_GUID('JonKey'),'333-333-333'),

encryptByKey(Key_GUID('JonKey'),'$50,000'))

insert into Fin.Clients values (4,'Trinity','Jon',

encryptByKey(Key_GUID('JonKey'),'444-444-444'),

encryptByKey(Key_GUID('JonKey'),'$300'))

--close all open keys

close all symmetric keys

--simulate logging out of Jon's context

REVERT

--TEST THE RESULTS--

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

Select * from Fin.Clients

Execute As login='Sheila'

--open the relevant keys for usage

OPEN SYMMETRIC KEY SheilaKey

DECRYPTION BY CERTIFICATE SheilaCert;

--Select from the table including decrypting

select id, clientname, investor,

convert(varchar,decryptbykey(SIN)) as SIN,

convert(varchar,decryptbykey(Portfolio)) as Portfolio

from Fin.Clients

--simulate logging out

Close all symmetric keys

REVERT

Execute As login='Jon'

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

--open the relevant keys for usage

OPEN SYMMETRIC KEY JonKey

DECRYPTION BY CERTIFICATE JonCert;

--Select from the table including decrypting

select id, clientname, investor,

convert(varchar,decryptbykey(SIN)) as SIN,

convert(varchar,decryptbykey(Portfolio)) as Portfolio

from Fin.Clients

--simulate logging out

Close all symmetric keys

REVERT

Note: It is also possible to achieve row level security without encryption as depicted in this article. I also recommend you check out this blog entry as well for a tool to assist with row level security.

With impersonate capabilities, you can now flow a single SQL context to the middle tier in the connection object, however, as part of the Command object you can now pass the end user –ASP.NET Principal Object which is derived from the HttpContext.User—to the database and have your middle account impersonate the end user. This provides the ability to flow just a single context in the connection object to ensure connection pooling for performance and by impersonating the end user and having the middle tier account context switch to the end use in the database auditing now be achieved at the database level. As shown in the illustration below:

--*****IMPERSONALIZATION DEMO*******

--*****WHO AM I******

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

--******Create Login Account SQLUser and Dan******

USE Master

Create login SQLUser with password='Capucci4!' --Middle Tier Account

Create login Dan with password='Capucci4!' --User to Impersonate

--*****Create Both Users in Database******

Use AdventureWorks

Create user SQLUser with DEFAULT_SCHEMA=HumanResources

Create user Dan with DEFAULT_SCHEMA=HumanResources

--*****Grant Permission to Middle Tier Account*****

Grant Select on HumanResources.Employee to SQLUser

Grant Select on HumanResources.Employee to Dan

--*****Allow SQLUser to Impersonate Dan******

GRANT IMPERSONATE ON USER:: Dan TO SQLUser

--*****Login as MiddleTier Account*****

--*****Connect to AdventureWorks Database*****

--*****Through the SQLConnection Object*******

Use AdventureWorks

Execute As Login='SQLUser'

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

--****Auditing Under SQLUser****************

Select EmployeeID, LoginID, SickLeaveHours

FROM HumanResources.Employee

Where SickLeaveHours > 75

--****Pass End User account ie.Dan--HttpContext.User—in

--****the command object***********

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

Declare @username varchar(25)

Set @username='Dan'

Execute as User=@username;

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

--****Auditing Under Dan****************

Select EmployeeID, LoginID, SickLeaveHours

FROM HumanResources.Employee

Where SickLeaveHours > 75

--*****Now reverted back to MiddleTier Account for

--*****connection pooling benefits******

REVERT

--****Now we are back as Middle Tier Acount********

SELECT SUSER_NAME() as LoginName, USER_NAME() as DBUserName;

On a final note, SQL Server 2005 releases a Community Technical Preview (CTP) of Service Pack 1 which can be downloaded here.

Code Scanning Tools' WebCast for on-demand viewing is available

dansellers — Fri, 17 Mar 2006 04:00:00 GMT

The on-demand version of the Visual Studio 2005 and Code Scanning Tools, conducted on March 15, 2006,by Kevin Lam and I, is now available for on-demand viewing.

Look forward to seeing everyone for next week webcast.

Webcast's Post Notes: Visual Studio 2005 and Code Scanning Tools

dansellers — Thu, 16 Mar 2006 04:35:00 GMT

In today’s webcast we had the opportunity to explore the buffer overrun attack in depth which is considered one of the worst vulnerabilities that exist. Any code that is written in C or C++ --without proper security code reviews--on any platform is susceptible to buffer overrun. It is becoming easier and easier to create shell code to pass as a parameter to our C or C++ code. For example, Kevin Lam --lead author of Assessing Network Security book--showed everyone the http://metasploit.com/shellcode.html web site.

In our Security November’s Webcasts we explored other common attacks such as:

SQL Injection
Cross Site Scripting
Canonical representation

But the underlying theme to prevent all of these types of attacks is validation our input, by checking and constraining all users’s input before passing the value to our resources. We should never pass user input directly into our code path and if we also ensure that our code runs as least privilege (hence the topic of our last two talks) then many of these attacks will become history.

Why was today’s webcast relevant to manage code? Because, a lot of us write manage code that p/invoke into Native code. Therefore, your manage code can be the path to vulnerabilities that may exist in native code.

In the second half of today’s presentation we explored code scanning tools such as:

PREfast
Application Verifier –standalone version download
FxCop

Each tool has their own pros and cons but the one thing that is common between all them of these tools by Microsoft or all other vendors is they are not a silver bullet. Code scanning tools have to limit the number of false positive to a minimal therefore; they will catch a lot of the low hanging fruit but miss a lot of the subtle security vulnerabilities. Code scanning tools on average will pick up about 50% of the security vulnerabilities in your applications and furthermore these tools can not verify a poor design that can lead to other security vulnerabilities. Therefore, your application is not designed with security in mind then code scanning tools will be of no value in these areas. I refer you to Michael Howard blog entry on his thoughts on code scanning tools.

Code Scanning tools need to become part of our security development lifecycle and not a replacement for proper security testing. Even with the best code scanning tools we will still need to do proper security code reviews, threat modeling and penetration testing.

The skill testing question today--is very open ended, but I have a list of few things I am looking for—is what are the cons with just using code scanning tools alone for securing your applications? I have three books “Writing Secure Code Edition 2” for the first three people that email me the correct answer through my blog.

Below is the snippet to the buffer overrun attack written in C:

/* ownMe.c : Buffer Overflow Demonstration
// Compile command from command-line: cl /Zi /GS- ownMe.c
// Command to execute: ownMe
// Works for: XP SP2 Tablet PC Version
// Additional instructions: For all three demos follow instructions then
// compile and run. The lines of code mantioned below are in main().
// Demo1 (No overflow): Uncomment line SayHello(Name); Comment other two lines
// Demo2 (Overflow and process crashes): Uncomment line SayHello(LongName); Comment other two lines
*/

#include "stdio.h"
#include "string.h"

char Name[] = "Mats Sundin";

char LongName[] =
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";

/*
*
*/
void SayHello(char * Name)
{
char NameBuffer[256];
strcpy(NameBuffer,Name);
printf("Hello %s",NameBuffer);
}

void main(void) {

SayHello(Name);
//SayHello(LongName);

}

On Demand WebCast: Least Privilege Development and New System.Security Features

dansellers — Fri, 10 Mar 2006 21:14:00 GMT

The latest Webcast "Least Privilege Development and New System.Security Features" which is part two of a five part series on examining the new security features and tools incorporated in Visual Studio 2005 and .NET Framework 2.0 is now ready for on-demand viewing and download.

Answer to the Trivial Question

dansellers — Thu, 09 Mar 2006 20:02:00 GMT

The answer to the trivial question from my blog based upon the March 8, 2006 WebCasts “Least Privilege Development and New System.Security Features” is below:

Question:

The KeyInfo element can consist of either a <KeyName/> or a <RetrievalMethod/> child element. What is the purpose of each element and what are the differences between the two elements?

Answer:

Both elements are used to provide additional information about KeyInfo:

KeyName - is a string identifying a key pair [key identifier]. Something along the lines of <!ELEMENT KeyName (#PCDATA)>

RetrievalMethod - on the other hand retrieval method is a reference to a remote source that can be used to gather information about the KeyInfo.

For instance, signatures in a document may use a key verified by a certificate chain appearing once in a document or remotely outside the document; where each signature's KeyInfo can reference this chain using a single RetrievalMethod.

Difference:

One element is a string that has the potential to indirectly identify a key while the other is used as direct reference.

We now have our three winners. Thank you everyone for attending the Webcast and look forward to seeing you next week.

WebCast's Notes: Least Privilege and New System.Security Features

dansellers — Thu, 09 Mar 2006 03:30:00 GMT

In today’s Webcast we first started off with a continuation from last week. Last week we explored how to setup a development and design environment that closely emulates your production environment to make your testing more effective and efficient. This was accomplished by enabling Debug in Zone and using tools such as permcalc. This week we explored another complimentary practice to better emulate your production and testing environment by designing and developing an application with a least privilege account.

In Visual Studio 2003 we needed to be a member of VS Developers to be to authorize Web Sites on the local computer or be a member of the Debugger User group to debug applications locally or remotely. Thus, by belonging to these groups we are increasing our privilege level. Therefore, in Visual Studio 2005 we have the ability to develop and debug application by only being a member of the built-in User group. By developing as a least privilege user it ensures that we can avoid a lot of the common LUA bugs. LUA bugs are introduced into your application when we develop and deploy an application which accesses resources that an End-User would normally not access if they only belong to the built-in User group. This result in either rewriting a portion of the application or worse of all--which occurs all too often is to increase the privilege level of the End-User to ensure the application will function properly.

Now of course developing under a least privilege account does expose certain challenging such as when you need to install software or make certain configuration changes that require administrative capabilities.

We could use RunAs however as mention there are some limitation when using RunAs alone.
Fast User Swithcing is another awesome strategy but this feature is disabled when your Windows XP machine belongs to a Domain.
Under Windows 2003 logging in as a user to develop your application and having a remote desktop open as Administrators works very well as demoed today.
Now if you are not using Windows 2003 then on Windows XP MakeAsAdmin overcomes a lot of the challenges of RunAs.

I recommend you review the following blogs:

In the second half of today’s WebCast we explored the use of SecureString. SecureString has a lot of advantages over System.String for storing sensitive information--as mentioned in the Webcast--but unfortunately if you want to use it for something like password etc it does not come with any UI component. As you can see from the bad login demo the clear text of password was still in the Text property of the TextBox control. However, in the Good login demo I was able to rectify this by using a Custom Windows Control that was derived from the standard TextBox control.

The SecureTextBox control can be downloaded here.
Other SecureString demo can be downloaded here.

Finally we explored the Crypto API that allows us to encrypt a portion or an entire XML document following W3C standards. In the demo I used a combination of both Asymmetric and Symmetric keys for both the encryption and signing a portion of the document.

The demo code from today application can be downloaded here:

And for today’s skill testing question:

The KeyInfo element can consist of either a <KeyName/> or a <RetrievalMethod/> child element. What is the purpose of each element and what are the differences between the two elements?

Hint: Cryptography.XML API follows the W3C standards which defines all elements in an encrypted XML document.

The first three people to email me the correct answer via this blog will have a chance to win a copy of the “Writing Secure Code Edition 2” book.

Partial Trust Development WebCast's Recording is now available for on-demand viewing

dansellers — Tue, 07 Mar 2006 05:43:00 GMT

Last Wednesday--March 1, 2006--I delivered part one of my five part WebCasts' series on the new tools and Security features in Visual Studio 2005 or .NET Framework 2.0. The recording of Part one--Partial Trust Development--is now available for viewing.

The Code Room: BREAKING INTO VEGAS!

dansellers — Sun, 26 Feb 2006 08:07:00 GMT

The Code Room is online ½ hour TV show focusing on developers and the programming challenges that they face.

The latest show, in a very, very cool way, will demonstrate the impact of a hacked environment (a casino in the show) that has been penetrated and compromised by a group of hackers. More importantly the show will also illustrate how to defend against the attack and the type of effort it takes to fix this.

My colleagues describe me as a Security wonk. Therefore, for other security wonks this is a must watch show (28 minutes). You can see the show in a number of places:

The Code Room: http://www.thecoderoom.com/vegas/

Channel 9: http://channel9.msdn.com/shows/The_Code_Room (you can also catch the first two episodes here and discuss about the show!)

MSDN TV: http://msdn.microsoft.com/msdntv/episode.aspx?xml=episodes/en/20060223CodeRoom3/manifest.xml

SECURITY ON THE BRAIN Webcast Series

dansellers — Thu, 23 Feb 2006 23:46:00 GMT

Wow! We currently have 1800 people registered for Security on the Brain Webcasts. There is still room, so if you want to learn more about developing secure software using Visual Studio 2005 and .NET Framework 2.0 then these five sessions for one hour every Wednesday, starting March 1, 2006 are for you.

I am just finalizing putting all the content together for the Webcasts and I am sure you find it very useful and informative. I plan to discuss the good and the bad about developing Secure Software and go heavy on the demos.

The more sessions you attend the better chances you have to win an Xbox 360. A brand new one…not mine!!! Now I thought that might get your attention!

After each Webcasts I will provide further details for area of interest that I did not have time to discuss in the Webcast on my blog.

Speaking of blogs, check out the new MSDN Canadian Developer blog that my colleagues, John Bristowe , Jerome Carron and I will blogging on as well. I will be mainly blogging on Security, whereas my colleagues will blog about other activities and technologies.