Password security often goes unappreciated until a breach occurs, highlighting the significance of strong passwords in preventing such incidents. Many users, however, remain unaware of the vulnerability of their passwords to common cracking methods. This article outlines three prevalent password-cracking techniques and strategies to defend against them.
Brute Force Attack
Brute force attacks involve using automated tools to systematically attempt all possible password combinations through repeated login attempts. Although these tools have existed for years, advancements in computing power and storage have made them more efficient, particularly when targeting weak passwords.
How it Works
Malicious actors employ various tactics in brute force attacks, ranging from simple brute force attacks that test every possible combination to more sophisticated approaches like hybrid and reverse brute force attacks. Each method has a unique strategy but shares the common goal of gaining unauthorized access to protected data or resources.
Popular automated tools used for brute force attacks include:
- John the Ripper: a password cracker that supports 15 operating systems and hundreds of hashes and cipher types
- L0phtCrack: a tool that utilizes rainbow tables, dictionaries, and multiprocessor algorithms to crack Windows passwords
- Hashcat: a utility that supports five unique attack modes for over 300 optimized hashing algorithms
Examples
In August 2021, a data breach at T-Mobile, initiated by a brute force attack, exposed over 37 million customer records containing sensitive information like social security numbers and driver’s license data.
Defense Measures
To protect against brute force attacks, users should adopt strong, complex passwords and enable multi-factor authentication. Administrators can implement account lockout policies and regularly audit their environments for weak and breached passwords using tools like Specops Password Auditor.
Dictionary Attack
A dictionary attack involves using a list of common passwords or words to gain access to an account or system. This attack type is particularly effective against weak or easily guessable passwords, emphasizing the importance of complex and unique passwords.
How it Works
The process involves compiling a list of potential passwords from data breaches, common password lists, or publicly available resources. Using automated tools, attackers systematically test each password against a target account or system until a match is found, allowing them to gain access.
Examples
Dictionary attacks have been used in high-profile security incidents, such as the 2013 Yahoo data breach and the 2012 LinkedIn data breach, resulting in the theft of billions of user account information.
Defense Measures
Users should create passwords that combine letters, numbers, and special characters, avoiding common words or easily guessable phrases. Administrators can enforce password complexity requirements in their policies and use tools like Specops Password Reset to facilitate secure password management.
Rainbow Table Attacks
Rainbow table attacks use precomputed tables of commonly used passwords and their corresponding hashes to crack password hashes in a database.
How it Works
Attackers create rainbow tables by hashing potential passwords and storing them alongside their plaintext counterparts. When they obtain a hash list, they can reverse-lookup each hash value in the rainbow table to find the corresponding plaintext password.
Examples
Although salting has reduced the effectiveness of rainbow table attacks, many hashes remain unsalted, and advancements in hardware have made these attacks more feasible.
Defense Measures
Implementing strong hashing algorithms like bcrypt or scrypt and regularly updating and rotating passwords can reduce the likelihood of rainbow table attacks. Tools like Specops Policy offer an additional layer of protection by scanning Active Directory against a database of breached passwords.
In conclusion, while passwords have their limitations, complex and sufficiently long passphrases remain a crucial first line of defense against advanced password-cracking techniques. Contact us for a free demo to learn more about enhancing your password security.