Database Security and SQL Injection Quiz

Database Security: SQL Injection Exploitation and Defense

• SQL injection exploitation is a technique used to gather information from network infrastructure and exploit database infrastructures.
• Common strategies for exploiting database infrastructures involve identifying common SQL statements and SQL constructs used to exploit weaknesses.
• Exploitation helps identify infrastructure weaknesses. Defense strategies against SQL injection exploits are also important.

Exploitation and Information Gathering

• Exploitation is the act of using system vulnerabilities for gaining access or control.
• Exploitation doesn't always lead to control.
• The effectiveness of SQL query injection techniques and the usefulness of the generated output impact exploitation.
• Security professionals need to know how to derive information and what information to protect to defend a system from successful exploitation.

Information That Aids in Exploitation

• Locating a weakness is the first step in an intrusion process.
• Attackers may gain access to a database without knowledge of its contents.
• The goal is to construct a theoretical picture of the infrastructure.
• Gathering details helps in obtaining access.
• Database schema is the overall logical structure of objects within the database, including stored procedures, tables, views, and users.

Information That Aids in Exploitation (cont'd.)

• Knowing the database vendor and version is crucial.
• With this information, the attacker can infer SQL language syntax for constructing injections.
• Default procedures, query processing methods, storage mechanisms, and large portions of the schema are also important.

Information That Aids in Exploitation (cont'd.)

• Identifying the vendor is easy for knowledgeable intruders.
• Multiple clues are needed to ascertain the database vendor and type.
• Clues include scripting languages, platforms, and database responses.

Information That Aids in Exploitation (cont'd.)

• Database vendors often use one or two programming languages.
• PHP is used to communicate with MySQL, .NET with SQL Server, and Oracle with Java Script.
• The platform is often related to the operating system, such as Microsoft SQL Server being based on Microsoft Windows Server 2008.

Information That Aids in Exploitation (cont'd.)

• Open-source operating systems are often used to support MySQL and Oracle.
• Database configuration is built on unique needs.
• Differences in syntax and error formats exist between databases.
• Error codes can provide valuable information, and vendors' websites often have information on error codes.

Information That Aids in Exploitation (cont'd.)

• Identifying the version of the database can be just as important as knowing the vendor.
• Knowing the version provides insight into system capabilities and vulnerabilities.
• Using standard queries to return the version number is a straightforward approach.

Information That Aids in Exploitation (cont'd.)

• Examples of commands to discover a version in SQL Server are: SELECT @@VERSION.
• This yields the SQL server version, processor, operating system, service pack, and build.
• Possible results of injecting a statement as a string parameter in a web application depend on if the application input/output has been filtered, and if the expected parameter is a string.

Information That Aids in Exploitation (cont'd.)

• If a statement is constructed incorrectly or if the expected parameter is a number, an error may occur.
• The message might contain the necessary information.
• If input/output is filtered, an application configured to handle error messages will not return an error message.

Information That Aids in Exploitation (cont'd.)

• Other standard statements are used to identify the database name, location, and language.
• Database administrators should familiarize themselves with such statements.
• These statements illustrate the amount of information potentially gathered during exploitation.

Extracting the Real Data

• Techniques in the previous sections allow intruders to gather basic information about the database.
• Based on this knowledge, intruders can craft meaningful queries to gather data.
• Exploitation attacks can help intruders gain deeper access to systems and extract the data they need.

Statement Exploits

• SQL statements can be injected into databases to varying extents.
• The intruder's capabilities depend on access as a typical user which might be restricted.

The UNION operator is a powerful SQL command that combines the results from two or more SELECT statements into a single result set. It is essential that all the SELECT statements have the same number of columns and those columns must also have

When employing UNION, duplicate rows are removed from the final result set unless UNION ALL is specified, which includes all rows, even duplicates. This feature can be particularly useful during data mining activities where an attacker seeks to consolidate information from different tables or databases.

Moreover, understanding how to use UNION effectively can allow database administrators to bolster their database security measures. They can implement strategies to recognize when unauthorized queries are being made, thus minimizing risk. Familiarity with these concepts not only aids in securing data but also enhances the ability to recover or audit data when necessary.

• UNION statements are powerful tools in SQL injection attacks.
• Attackers can use them to append their queries to legitimate SQL statements.
• An example of a using UNION statement on an example website address such as (http://www.yum.com/index.asp?category=dairy union select Table_Name from Information_Schema.Tables) can be used to determine the table name in the database.

Using UNION (cont'd.)

• Combining results from various queries and displaying them is a core goal of UNION statements.
• Provided syntax should be correct.
• Using Table_Name, a call can ask the database to provide names of all tables in a specific database.
• Removing the error message can help in determining the number of columns being used in an original query.

Using UNION (cont'd.)

• A strategy to determine the number of columns is to keep adding null to the SQL statement until the error message disappears.
• The data type of columns can also be determined through trial and error.
• Automated tools are available to expedite this process.

Using UNION (cont'd.)

• Automated tools are available to aid users in simplifying the process of combining results from multiple SELECT queries. These tools can enhance efficiency and accuracy, often allowing for graphical interfaces that guide users through complex operations without manual coding.

• Column_Name can be used in place of Table_Name in SQL statements to retrieve specific column data from tables. This approach allows users to focus on the individual fields they need, facilitating targeted data analysis and reducing the volume of unnecessary information processed.

• .

Using Conditions

• Conditional statements allow attackers to perform a specific action if a condition is true or an alternative action if a condition is false.
• This is useful in situations where UNION statements aren't allowed.
• Examples include testing if a user is an administrator.

Using Conditions (cont'd.)

• Generating error messages can alert system administrators to intruder actions.
• Time-based responses cause delays in conditional response time to help an attacker identify answers.

Large-Scale Extraction

• Previously presented strategies can be tedious, but effective at providing intruders with data for extending their search.
• Combining strategies allows for database extraction at a larger scale.

Large-Scale Extraction (cont'd.)

• Getting database names is a crucial first step.
• Listing accessible databases for targeting is followed by extracting table and column names.
• Statements used to extract database names depend on the database platform.

Large-Scale Extraction (cont'd.)

• Approaches to extract table names include identifying the table that holds the names of all database tables.
• Statements for finding tables vary by platform.

Large-Scale Extraction (cont'd.)

• Extracting columns involves using specific statements to identify the columns in a database.
• Different statements are required to achieve this based on the database platform.

Advanced Techniques

• Filters in web applications serve the critical purpose of detecting and preventing various forms of injection attacks, such as SQL injection, Cross-Site Scripting (XSS), and command injections. These filters act as a security measure that analyzes the input data and ensures that it conforms to expected formats, effectively mitigating the risks posed by malicious actors seeking to exploit vulnerabilities.
• Techniques for evading filters include various methods such as character changes, where attackers modify the input by altering characters to bypass detection. Additionally, encoding techniques are frequently employed, transforming harmful payloads into seemingly benign data, complicating the filtering process. These evasion tactics highlight the ongoing cat-and-mouse game between developers and attackers, necessitating the continual improvement of filtering mechanisms.

Advanced Techniques (cont'd.)

• Case sensitivity is a technique where the case of keywords is altered to avoid detection.
• URLs can be used to break down common words.
• Alternative statements such as case statements can be used as a substitute for If... Then statements.

Exploitation of Privileges and Passwords

• Success depends on permissions of the target user.
• Limiting factors for intruders exist.
• Privileges are identified and increased, if possible.

Identifying Privileges

• Knowing which privileges are grantable on a system is critical.
• Locating and viewing privilege tables is a key part.
• Specific SQL statements are used to identify available grantable privileges.

Obtaining Passwords

• Passwords are often stored as hashes (nonreversible).
• Privileges are required to view password hashes in tables.

Obtaining Passwords (cont'd.)

• Passwords are often cryptographically encoded strings.
• Extracting them can sometimes prove difficult.
• Passwords in text form represent a risk to data integrity.

Obtaining Privileges (cont'd.)

• Brute-force attacks involve iterative trials using every possible combination, and their effectiveness depends on the amount of known background information.
• Automated tools are available for privilege escalation to gather more information.

Obtaining Privileges (cont'd.)

• Using OPENROWSET is a common procedure for escalating SQL Server privileges.
• It allows remote database connection to retrieve information using alternative credentials.
• Timeouts are not present for failed login attempts.

Obtaining Privileges (cont'd.)

• E-mail can be used for escalating privileges.
• Modern database systems often send alerts or passwords to administrators for account security.

Defending Against Exploitation

• Learning about system weaknesses and monitoring for possible attacks are key defense strategies.
• Combining approaches creates a strong defense.

Using Bond Parameters

• Using bond parameters for user input protects against SQL injection by separating data from the SQL statement.
• The input is treated as user data and, therefore, does not affect the SQL statement.

Sanitizing Data

• Using word blocking to deny known non-allowed keywords is a technique for protecting against SQL injections.
• Filtering keywords is a useful approach to identify and limit input data.

Restricting and Segregating Databases

• Assigning specific database privileges limits the scale of access permissions.
• Preventing errors from being processed by web applications is key.
• Database servers should have minimum permissions.
• Segregating web and database servers is a key security approach.

Security-Conscious Database Design

• Database infrastructure design must consider how data is stored, how objects are named, and what information is made accessible.
• Defaults and object views can expose sensitive information.
• A honeypot environment can be used to mislead intruders.

Diligent Monitoring

• Thorough monitoring is important to security.
• Tracking errors can point to ongoing attacks.
• Alert thresholds based on baselines can be helpful.

Summary

• Understanding the database schema is a crucial goal for stopping SQL injection attacks.
• More database information increases the risk of successful attacks.
• Errors including vendor information can give attackers clues.
• UNION statements are powerful tools.
• Conditional statements help attackers gain more access.

Summary (cont'd.)

• Several techniques help intruders evade web application filters.
• Escalating privileges through different approaches can cause serious security risks.
• Segregating database servers helps better monitor and prevent exploitation.

Test your knowledge on database security and SQL injection techniques with this quiz. Explore concepts related to intruder tactics, security protocols, and effective database management practices. Ideal for students and professionals looking to enhance their understanding of database vulnerabilities.