Understanding SQL Injection Attacks

Posted by in Security+ | 0 comments

SQL injection attacks are all too common, but they are easy to identify, and relatively easy to protect against.

Many web sites use SQL statements to interact with a database providing users with dynamic content. If you’re planning on taking the Security+ exam, you should have a good understanding of how attackers launch a SQL injection attack.

For example, can you answer this question?

Q. Attackers have attacked an online web server using a SQL injection attack. Which of the following BEST describes this?

A. The attacker is attempting to overload the system with unexpected data and access memory locations.

B. The attacker is attempting to impersonate a user using HTML code.

C. The attacker is sending random data into a program to see if the application will crash.

D. The attacker is attempting to pass commands to a back-end database server to access data.

More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.

Get Certified Get Ahead

How SQL Injection Attack Works

In a SQL injection attack, the attacker enters additional data into the web page form to generate different SQL statements. SQL query languages use a semicolon (;) to indicate the end of the SQL line and use two dashes (–) as an ignored comment. With this knowledge, the attacker could enter different information into the web form like this:

Darril Gibson; SELECT * FROM Customers;–

If the web application plugged this string of data directly into the SELECT statement surrounded by the same single quotes, it would look like this:

SELECT * FROM Books WHERE Author = ‘Darril Gibson’;

SELECT * FROM Customers;

–’

The first line retrieves data from the database, just as before. However, the semicolon signals the end of the line and the database will accept another command. The next line reads all the data in the Customers table, which can give the attacker access to names, credit card data, and more. The last line comments out the second single quote to prevent a SQL error.

Full Security+ Course

Full Security+ Course Now Available

Helping you Pass the First Time

Online access includes all of the content from the

CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide

  • Introduction
  • About the exam (including types of questions and strategies for performance-based questions)
  • 100 question pre-assessment exam
  • Mastering Security Basics (full content from Chapter 1 of the study guide including the exam topic review and 20 practice test questions)
  • Exploring Control Types and Methods (full content from Chapter 2 of the study guide including the exam topic review and 20 practice test questions)
  • Understanding Basic Network Security (full content from Chapter 3 of the study guide including the exam topic review and 20 practice test questions)
  • Securing Your Network (full content from Chapter 4 of the study guide including the exam topic review and 20 practice test questions)
  • Securing Hosts and Data (full content from Chapter 5 of the study guide including the exam topic review and 20 practice test questions)
  • Understanding Malware and Social Engineering (full content from Chapter 6 of the study guide including the exam topic review and 20 practice test questions)
  • Identifying Advanced Attacks (full content from Chapter 7 of the study guide including the exam topic review and 20 practice test questions)
  • Managing Risk (full content from Chapter 8 of the study guide including the exam topic review and 20 practice test questions)
  • Preparing for Business Continuity (full content from Chapter 9 of the study guide including the exam topic review and 20 practice test questions)
  • Understanding Cryptography (full content from Chapter 10 of the study guide including the exam topic review and 20 practice test questions)
  • Exploring Operational Security (full content from Chapter 11 of the study guide including the exam topic review and 20 practice test questions)
  • 100 question post-assessment exam
  • Security+ Acronyms

Get the Full Security+ Course Here

 Full Security+ Course Now Available


Test your readiness with these quality materials

Random 100-question tests

Random practice tests from the all of the practice test questions in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide. All questions include explanations so you'll know why the correct answers are correct, and why the incorrect answers are incorrect.

34 Simulated Performance-based Questions

Eight sets of performance-based questions with multiple questions in each set. These questions help you understand and prepare for performance based questions.

22 Realistic Performance-based Questions

Two new sets of performance-based questions with a total of 22 questions. These new questions use a new testing engine that includes realistic drag and drop, matching, sorting, and fill in the blank questions.

Flashcard Set

  • 273 Security+ Flashcards to reinforce key testable concepts
  • 280 Security+ acronyms flashcards to help you master the required acronyms
  • 204 Security+ Remember This slides

Audio - SY0-401 Security+ Remember This Audio Files

Learn by Listening. Over one hour and 15 minutes of audio (MP3 downloads.)

Audio - SY0-401 Security+ Question and Answer Audio Files

Learn by Listening. Over three hours hour and 15 minutes of audio (MP3 downloads.)

Bonus #1

Audio from the end of chapter reviews from each of the chapters in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide. Over one hour and 15 minutes of additional audio.

Bonus #2

Subnetting mini-tutorial that will help you answer two key question types:
  • Identify how many hosts a subnet supports
  • Identify valid IP addresses within a subnet

Bonus #3 

Access the study materials for a total of 60 days because sometimes life happens.

Get the Full Security+ Course Here

If the application doesn’t include error-handling routines, these errors provide details about the type of database the application is using, such as an Oracle, Microsoft SQL Server, or MySQL database. Different databases format SQL statements slightly differently, but once the attacker learns the database brand, it’s a simple matter to format the SQL statements required by that brand. The attacker then follows with SQL statements to access the database and may allow the attacker to read, modify, delete, and/or corrupt data.

This attack won’t work against Amazon (please don’t try it) because Amazon is using secure coding principles. I don’t have access to its code, but I’d bet their developers are using input validation and SQL-based stored procedures.

SQL Injection Attack

Many SQL injection attacks use a phrase of or 1 = 1‘ to create a true condition. For example, if an online database allows you to search a Customers table looking for a specific record, it might expect you to enter a name. If you entered Homer Simpson, it would create a query like this:

SELECT * FROM Customers WHERE name = ‘Homer Simpson’

This query will retrieve a single record for Homer Simpson. However, if the attacker enters ‘ or ‘1’=’1′ — instead of Homer Simpson, it will create a query like this:

SELECT * FROM Customers WHERE name = ‘ ‘ or ‘1’=’1′ –‘

Although this is a single SELECT statement, the or clause causes it to behave as two separate SELECT statements:

SELECT * FROM Customers WHERE name = ‘ ‘

SELECT * FROM Customers WHERE ‘1’=’1′

Note: The clause or ‘1’=’1′ –‘ is a dead giveaway informing you that this is a SQL injection attack. If you see this in a log entry, it should ring some alarm bells for you. If you see this in an exam question, you should think about SQL injection attacks.

CompTIA Security+ Study Guide (SY0-401)

The 401 Version of the Study Guide is Now Available

SY0-401 Study GuideThe CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide is an update to the top-selling SY0-201 and SY0-301 study guides, which have helped thousands of readers pass the exam the first time they took it.

CompTIA Authorized Quality Content (CAQC)After a comprehensive review by ProCert Labs, the SY0-401 version has been certified as CompTIA Approved Quality Content (CAQC) and covers every aspect of the SY0-401 exam.

It includes the same elements readers raved about in the previous two versions.

Each of the eleven chapters presents topics in an easy to understand manner and includes real-world examples of security principles in action.

You’ll understand the important and relevant security topics for the Security+ exam, without being overloaded with unnecessary details. Additionally, each chapter includes a comprehensive review section to help you focus on what’s important.


Click for Free Preview


Over 400 realistic practice test questions with in-depth explanations will help you test your comprehension and readiness for the exam. The book includes:

  • A 100 question pre-test
  • A 100 question post-test
  • Practice test questions at the end of every chapter.

Each practice test question includes a detailed explanation to help you understand the content and the reasoning behind the question. You’ll be ready to take and pass the exam the first time you take it.

If you plan to pursue any of the advanced security certifications, this guide will also help you lay a solid foundation of security knowledge. Learn this material, and you’ll be a step ahead for other exams. This SY0-401 study guide is for any IT or security professional interested in advancing in their field, and a must read for anyone striving to master the basics of IT security.

Kindle edition also available.

The first clause will likely not return any records because the table is unlikely to have any records with the name field empty. However, because the number 1 always equals the number 1, the WHERE clause in the second statement always equates to True, so the SELECT statement retrieves all records from the Customers table.

In many cases, a SQL injection attack starts by sending improperly formatted SQL statements to the system to generate errors. Proper error handling prevents the attacker from gaining information from these errors, though. Instead of showing the errors to the user, many web sites simply present a generic error web page that doesn’t provide any details.

Remember this

Attackers use SQL injection attacks to pass queries to back-end databases through web servers. Many SQL injection attacks use the phrase ‘ or ‘1’=’1′ – to trick the database server into providing information.

Input validation and stored procedures reduce the risk of SQL injection attacks.


Security+ Practice Test Questions

SYO-401 Practice Test Questions Now Available

Over 440 realistic Security+ practice test questions

All questions include explanations so you'll know why the correct answers are correct,

and why the incorrect answers are incorrect.

Pass the Security+ Exam

the First Time You Take It

Multiple quiz formats to let you use these questions based on the way you learn.
  • Learn mode - randomized. View each of the questions in random order. Learn mode allows you to keep selecting answers until you select the correct answer. Once you select the correct answer, you'll see the explanation. Click here to see how learn mode works.
  • Learn mode - not randomized. View each of the questions in the same order. Use this if you want to make sure that you see all of the questions. Learn mode allows you to keep selecting answers until you select the correct answer. Once you select the correct answer, you'll see the explanation. Click here to see how learn mode works.
  • Test mode - randomized. View each of the questions in random order. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.
  • Test mode - not randomized. View each of the questions in the same order. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.
  • Test mode - 100 random questions. View 100 random questions from the full test bank similar to how the Security+ exam has a potential maximum of 100 multiple choice questions. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.

Get the full bank of Security+ Practice Test Questions Here

 SYO-401 Practice Test Questions Now Available


INCLUDES QUESTIONS TO HELP YOU PREPARE

FOR THE NEW PERFORMANCE BASED QUESTIONS 

Bonus - Performance Based Questions

Additional Security+ questions to help you prepare for the new performance based questions. These are included with the full bank of Security+ practice test questions and are divided into different sections. For example, you'll have access to the following links:

- Performance Based Question - Set 1

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of security to mobile devices and servers in a data center. You'll then have two questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 2

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of attacks with the name of the attack type. You'll then have five questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 3

You'll see a graphic showing a network with computers and servers separated by a firewall. The firewall is used to control traffic between the computers and users using rules within an access control list (ACL).  You'll have three questions that test your knowledge and ability to correctly identify the relevant components of the rule. The incorrect answers and explanation provide you with insight into how to correctly answer this type of question on the actual exam.

- Performance Based Question - Set 4

You'll see a graphic explaining what you might be required to do on the actual exam related to what a forensic analyst would do during an investigation. You'll then have two questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 5

You'll see a graphic explaining what you might be required to do on the actual exam to match protocols and ports. You'll then have seven questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 6

You'll see a list of security controls along with a graphic showing devices and locations within an organization, along with instructions on what you might be required to do on the actual exam to match the controls with the devices and locations. You'll then have four questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 7

You'll see a list of authentication methods and authentication factors along with instructions on what you might be required to do on the actual exam to match the authentication methods with the authentication factors. You'll then have six questions that test your knowledge and ability to correctly answer the questions. This set also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 8

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of attacks with the name of the attack type. You'll then have five questions that test your knowledge and ability to correctly answer the questions. This is similar to Set 2 but expands on the possibilities. The set also includes a link to a page showing the end solution for the overall performance based question simulation.

New - Performance Based Question - Set 9

New questions recently added using a different testing engine. See a demo here. This set includes drag and drop and matching questions on ports.

New - Performance Based Question - Set 10

A random set of 20 performance-based questions using drag and drop, matching, sorting, and fill in-the blank. This set includes performance-based questions on RAID.

Get the full bank of Security+ Practice Test Questions Here

Get the full bank of Security+ Practice Test Questions

Q. Attackers have attacked an online web server using a SQL injection attack. Which of the following BEST describes this?

A. The attacker is attempting to overload the system with unexpected data and access memory locations.

B. The attacker is attempting to impersonate a user using HTML code.

C. The attacker is sending random data into a program to see if the application will crash.

D. The attacker is attempting to pass commands to a back-end database server to access data.

Answer is D. In a SQL injection attack, an attacker attempts to inject SQL commands into a query to access or manipulate data on a back-end database.

A buffer overflow attack attempts to overload a system with too much data or unexpected data in an attempt to access system memory.

A cross-site request forgery (XSRF) attack attempts to impersonate a user with HTML code.

Fuzzing is a testing technique that sends random data into an application to see if the application can handle it.

See Chapter 7 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide for more information on advanced attacks.

Leave a Comment

CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide

Subscribe To Our Newsletter

Join our mailing list and get a free excerpt of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide.  This excerpt includes the introduction and Chapter 1. 

You have Successfully Subscribed!

Get Certified Get Ahead is a participant in the Amazon Services LLC Associates Program,
an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.

Copyright © 2015 Get Certified Get Ahead. All Rights Reserved.