Password Attacks

Posted by in Security+ | 0 comments

Password attacks attempt to discover or bypass passwords used for authentication on systems and networks, and for different types of files. Although there are many attack methods, they fall into two generic categories: online password attacks and offline password attacks.

An online password attack attempts to discover a password from an online system. For example, an attacker trying to log on to an account by trying to guess a user’s password is an online attack.

Offline password attacks attempt to discover passwords from a captured database or captured packet scan. For example, when attackers hack into a web site causing a data breach, they can download entire databases. They then perform offline attacks to discover the passwords contained within the databases. Similarly, Wi-Fi Protected Access (WPA) cracking attacks first capture the four-way handshake when WPA wireless clients authenticate with a wireless access point. After capturing these packets, they perform an offline attack to discover the WPA password.

The following sections cover some specific types of password attacks and this blog covers others such as rainbow table attacks.


Pass the Security+ exam the first time

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

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


Brute Force Password Attacks

A brute force attack attempts to guess all possible character combinations. One of the best protections against offline brute force attacks is to use complex passwords. Complex passwords include a mix of uppercase letters, lowercase letters, numbers, and special characters. Additionally, longer passwords are much more difficult to crack than shorter passwords.

Account lockout policies are effective against online brute force attacks. An account lockout setting locks an account after the user enters the incorrect password a preset number of times.

Additionally, key stretching techniques such as bcrypt and Password-Based Key Derivation Function 2 (PBKDF2) add a salt to the password and are effective against brute force attacks.

Security+ Practice Test Questions

SY0-501 Practice Test Questions 

Over 300 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 - 75 random questions. View 75 random questions from the full test bank similar to how the Security+ exam has a potential maximum of 75 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 SY0-501 Practice Test Questions Here

 SY0-501 Practice Test Questions


INCLUDES QUESTIONS TO HELP YOU PREPARE

FOR THE NEW PERFORMANCE BASED QUESTIONS 

Bonus - Performance Based Questions

Three sets of performance-based questions including over 30 questions. These questions show you what you can expect in the live exam. They include drag and drop, matching, sorting, and fill in the blank questions. See a demo here.

Bonus - Extra Practice Test Questions

New multiple-choice questions in the extra test bank. Questions are added occasionally. You can see what has been added recently here.

Get the full bank of Security+ (SYO-501) Practice Test Questions Here

Get the full bank of Security+ Practice Test Questions

Click here if you're looking for SY0-501 Full Study Package

Dictionary Password Attacks

One of the original password attacks uses a dictionary of words and attempts to use every word in the dictionary to see if it works. Dictionaries used in these attacks evolved over time and included many of the common passwords that uneducated users configured for their accounts. For example, even though 12345 isn’t a dictionary word, many people use it as a password, so characters such as these have been added to many dictionaries used by dictionary attack tools.

These attacks are thwarted by using complex passwords. A complex password will not include words in a dictionary.

Password Hashes

Most systems don’t store the actual password for an account. Instead, they store a hash of the password. Hash attacks attack the hash of a password instead of the password. A hash is simply a number created with a hashing algorithm such as MD5 or SHA-1. A system can use a hashing algorithm such as Message Digest 5 (MD5) to create a hash of a password.

As an example, if a user’s password is IC@nP@$$S3curity+, the system calculates the hash and stores it instead. In this example, the MD5 hash is 75c8ac11c86ca966b58166187589cc15. Later, a user authenticates with a username and password. The system then calculates the hash of the password entered by the user and compares the calculated hash against the stored hash. If they are correct, it indicates the user entered the correct password.

Similarly, systems rarely send passwords across a network. Instead, they send the hash of the password and normally in an encrypted format.

Unfortunately, tools are available to discover many hashed passwords. For example, MD5 Online allows you to enter a hash and it gives you the text of the password. If the password is 12345, the hash is 827ccb0eea8a706c4c34a16891f84e7b. If you enter that hash into MD5 Online, it returns the password of 12345 in about a second. MD5 Online uses a database of hashed words from a dictionary. If the hash matches a database entry, the site returns the password.

Other password attacks such as rainbow table attacks are covered in this blog post.

0 Comments

Trackbacks/Pingbacks

  1. Key Stretching - Get Certified Get Ahead | Get Certified Get Ahead - […] complex passwords goes a long way toward preventing brute force attacks and rainbow table attacks but doesn’t prevent them all.…
  2. Rainbow Table Attacks - Get Certified Get Ahead | Get Certified Get Ahead - […] Rainbow table attacks, birthday password attacks, and hybrid attacks are discussed in this post. Other password attacks are covered…

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

CompTIA Security+ Get Certified Get Ahead: SY0-501 Study Guide

Subscribe To Our Newsletter

Join our mailing list and get a free excerpt of the CompTIA Security+: Get Certified Get Ahead: SY0-501 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.