This technique is notably used in Microsoft Azure SQL, a cloud-based SQL database, which offers excellent protection of sensitive data for administrators. The Administrative exam for Microsoft Azure SQL Solutions, DP-300, frequently tests understanding and application of this technique. In this article, we will take a deep dive into Dynamic Data Masking, outlining its implementation and advantages.
1. Understanding Dynamic Data Masking (DDM)
Azure SQL’s Dynamic Data Masking feature allows administrators to conceal sensitive data in the result set of a query. This ensures that unauthorized users cannot access sensitive data while having regular access to non-sensitive data. It enables you to determine how much data you want to mask in a particular field.
DDM can be implemented without impacting the stored database as the masking rules are applied only when the data is queried. This means you don’t have to change the way your application queries the data or how the data is stored which makes it an extremely flexible solution.
2. How to Implement Dynamic Data Masking
To illustrate the implementation of DDM, assume we have a Customer table that includes fields such as CustomerID, FirstName, LastName, Email, and CreditCardNumber.
CREATE TABLE Customer
(
CustomerID int IDENTITY(1,1) PRIMARY KEY,
FirstName nvarchar(100),
LastName nvarchar(100),
Email nvarchar(100),
CreditCardNumber nvarchar(16)
)
Now, we want to apply DDM to protect the fields Email, and CreditCardNumber. You can add a mask to these fields using the following commands:
ALTER TABLE Customer
ALTER COLUMN Email ADD MASKED WITH (FUNCTION = 'email()')
ALTER TABLE Customer
ALTER COLUMN CreditCardNumber ADD MASKED WITH (FUNCTION = 'partial(0,"XXXX-XXXX-XXXX-",4)')
In the above commands, ’email()’ is a pre-defined masking function that will expose the first letter of the email and the suffix at ‘.com’, ‘.org’, etc., but mask all other characters with an ‘x’. ‘partial(0,”XXXX-XXXX-XXXX-“,4)’ is another function stating that the last 4 characters would be visible while the rest of the card number would be masked.
3. Viewing Data With and Without Masking
Once you have applied the masking rules, if a privileged user (like the database owner or a member of the db_owner role) runs a SELECT statement, they will see the original unmasked data. However, other users will get the masked data.
Here is what each user would see:
| Credit Card Number | ||
| Privileged User | john@doe.com | 1234-5678-1234-5678 |
| Regular User | jxxx@xxxx.com | XXXX-XXXX-XXXX-5678 |
4. Controlling Access to Masked Data
You can also grant the `UNMASK` privilege to specific roles or users if they need to see the original data.
GRANT UNMASK TO privilegeduser;
To revoke the same privilege, you use:
REVOKE UNMASK TO privilegeduser;
5. Conclusion
In today’s data-sensitive world, features like DDM are increasingly essential. DDM helps protect sensitive data from unauthorized users, providing an important layer of security within your applications. By understanding and implementing techniques like those covered within Azure SQL’s DP-300 exam, administrators can fully leverage the capabilities of Azure SQL and ensure their data is well protected.
Practice Test
True or False: Dynamic Data Masking (DDM) is used to limit sensitive data exposure by masking it to non-privileged users.
- True
- False
Answer: True
Explanation: DDM is a security feature that hides sensitive data in the result set of a query over designated database fields, while the data in the database remains unchanged.
The dynamic data masking feature is available in which of the following?
- Microsoft Azure SQL
- Oracle Database
- MongoDB
Answer: Microsoft Azure SQL
Explanation: Dynamic Data Masking is a feature available in Microsoft Azure SQL Database which helps to prevent unauthorized access to sensitive data.
Which of the following is a type of dynamic data masking function in Microsoft Azure SQL Database?
- Default
- Individual
- Single
Answer: Default
Explanation: The types of dynamic data masking functions include Default, Email, SSN, and Custom String.
True or False: Dynamic data masking can help prevent unauthorized access to sensitive data, but it cannot totally stop SQL Injection attacks.
- True
- False
Answer: True
Explanation: Although DDM helps prevent unauthorized access to sensitive data, it is not a comprehensive security solution and cannot stop SQL Injection attacks on its own.
Implementing dynamic masking requires considerable downtime in the database.
- True
- False
Answer: False
Explanation: Implementing dynamic masking in Microsoft Azure SQL Database does not require downtime or changes in application code.
Can Dynamic Data Masking be used with on-premise SQL servers?
- Yes
- No
Answer: Yes
Explanation: Yes, Dynamic Data Masking is supported on both Azure SQL databases and on-premise SQL servers.
Which function can be used to mask the entire string of characters in an email except for the suffix in the email domain area with ‘x’ characters?
- Credit
- Social
Answer: Email
Explanation: The Email masking function exposes the first letter of an email address and replaces all other characters in the email name with ‘x’ characters, and exposes the constant suffix ‘.com’.
Who can manage the Dynamic Data Masking policy rule?
- Database owners
- Azure RBAC role
- Power BI role
Answer: Database owners
Explanation: Database owners and members of the db_owner role can manage the Dynamic Data Masking policy rules.
Can you unmask data using SELECT INTO and BULK INSERT statements in SQL after applying DDM?
- Yes
- No
Answer: Yes
Explanation: It’s possible to unmask data using SELECT INTO and BULK INSERT statements in SQL. However, these options are typically utilized for administrative purposes.
Dynamic Data Masking supports masking for which of the following types of data?
- Text
- Numeric
- Both
Answer: Both
Explanation: Dynamic Data Masking supports a variety of data types including text and numeric types.
True or False: Dynamic data masking operation requires data encryption in the database.
- True
- False
Answer: False
Explanation: Dynamic data masking operation does not require data encryption in the database. The data remains intact and is not physically changed.
Interview Questions
What is dynamic data masking in Azure SQL?
Dynamic data masking in Azure SQL is a security feature that hides sensitive data in the result set of a query over designated database fields, while the data in the database remains unchanged.
What is the main purpose of implementing dynamic data masking?
The main purpose of implementing dynamic data masking is to restrict sensitive data in the database from unauthorized access. It helps prevent data exposure in a set of predefined scenarios.
What types of data can be masked with dynamic data masking in Azure SQL?
Azure SQL Dynamic Data Masking can mask various types of data like Credit Card Numbers, Email Addresses, Social Security Numbers, and other custom text or numeric data.
Can the dynamic data masking be turned off once it’s applied in Azure SQL?
Yes, the dynamic data masking can be turned off or removed by applying a new masking rule without masking function.
Who can set up dynamic data masking in Azure SQL?
Only the database administrators or users with sufficient privileges can set up dynamic data masking in Azure SQL.
Can you list a few masking functions used in Azure SQL dynamic data masking?
A few examples of masking functions used in Azure SQL dynamic data masking include Default(), Credit Card(), Email() and Custom Text().
What does the Default() masking function do in Azure SQL dynamic data masking?
The Default() masking function provides a default mask for a given data type. For example, for string data types, it exposes the first and last characters and adds a custom padding string in the middle.
Is it possible to mask specific portions of a column’s data in Azure SQL?
Yes, with the help of the Custom Text() masking function in Azure SQL, you can mask specific portions of a column’s data.
Does dynamic data masking in Azure SQL provide encryption?
No, dynamic data masking does not provide encryption. The data remains unencrypted in the database and only masked to those who do not have the unmask privilege.
Are the database index operations impacted by dynamic data masking?
No, the database index operations are not impacted by dynamic data masking as the data in the database remains unchanged.
How can you view the unmasked data in Azure SQL?
The unmasked data in Azure SQL can be viewed by users who have the ‘UNMASK’ database permission or by members of the ‘db_owner’ role.
How can you add a dynamic data masking rule in Azure SQL?
To add a dynamic data masking rule in Azure SQL, you can use the Azure portal, PowerShell, or Transact-SQL by specifying the schema, table, and column to which the masking rule applies.
Can you remove an existing dynamic data masking rule in Azure SQL?
Yes, an existing dynamic data masking rule can be removed in Azure SQL using the Azure portal, PowerShell, or Transact-SQL.
Are there any limitations related to dynamic data masking in Azure SQL?
Yes, there are some limitations. For example, dynamic data masking does not mask data in direct database exports or in backup files.
What does the Email() masking function do in Azure SQL dynamic data masking?
The Email() masking function exposes the first character of an email address and replaces all other characters with ‘x’, except for the constant suffix ‘@xxxx.com’.
extutorials.com