🔹What is Rainbow table Attack
A rainbow table attack is a type of password cracking method that uses precomputed tables containing hashes and their corresponding plaintext passwords. The attacker compares the hash of a target password with those in the table to find a match and recover the original password. This attack can be prevented by using strong and unique passwords, adding a salt to the hash, and using a slow hashing algorithm.
Rainbow table attacks are often used by hackers to exploit weak or easily guessable passwords, as they can quickly recover the original password without having to perform the computationally intensive hashing process for each guess.
To create a rainbow table, the attacker first generates a large set of plaintext passwords, computes their hashes using a particular hashing algorithm, and stores them in a table. The table is then searched for a matching hash value when attempting to crack a password.
One way to defend against rainbow table attacks is to use a strong and unique password for each account. Longer passwords that include a mix of upper and lowercase letters, numbers, and symbols are harder to crack. Additionally, adding a salt - a random value added to the password before hashing - makes it more difficult to create precomputed tables.
Finally, using a slow hashing algorithm such as bcrypt, scrypt, or Argon2 can slow down the attacker's ability to generate and compare hashes, making the attack more difficult and time-consuming.
🔹How to Work Rainbow table Attack
A rainbow table attack works by precomputing a large table of encrypted passwords and their corresponding plaintext values, which is called a rainbow table. The rainbow table is generated by starting with a starting plaintext value, encrypting it, and then reducing the resulting hash to a new plaintext value. This process is repeated several times, with each resulting plaintext value being encrypted and reduced, until a final plaintext value is obtained.
Once the rainbow table has been generated, the attacker can use it to crack passwords. To do this, the attacker first obtains the hashed password they want to crack, which is typically obtained by intercepting network traffic or by stealing a password database. The attacker then looks up the hashed password in the rainbow table, which will return the corresponding plaintext value. If the plaintext value is the actual password, then the attacker has successfully cracked the password.
However, because rainbow table attacks are limited to precomputed values, they are only effective against weak passwords that can be found in the precomputed table. To defend against rainbow table attacks, strong passwords that are resistant to precomputation should be used, and additional measures such as salting and key stretching can be employed to further increase the security of password storage.
🔹Creating a Table
Here, the hash of a string is taken and then reduced to create a new string, which is reduced again, repeatedly. For example, let’s create a table of the most common password, 12345678, using MD5 hash function on first 8 characters:
First we take the string and pass it through md5 hash function.
hashMD5(12345678) = 25d55ad283aa400af464c76d713c07ad
We reduce the hash by taking only the first 8 characters. Then, we re-hash it.
hashMD5(25d55ad2) = 5c41c6b3958e798662d8853ece970f70
This is repeated until enough hashes in output chain. This represents one chain, which starts from the first plain text and ends at the last hash.
After obtaining enough chains, we store them in a table.
🔹Cracking the Password
Starting off with the hashed text (the password) is checked if it exists in the database. If so, go to the start of the chain and start hashing until there is a match. As soon as the match is obtained, the process ceases and the authentication is cracked. The following flowchart explains the steps:
🔹Advantages and Disadvantages of Rainbow Table Attack
Rainbow table attacks are a type of password cracking method that involves precomputing and storing hashes of possible passwords. Here are some advantages and disadvantages of rainbow table attacks:
Advantages:
- Rainbow table attacks can be very fast and efficient, as the attacker does not need to perform any additional computations or make multiple attempts to crack a password.
- They can be automated, making it possible for an attacker to crack large numbers of passwords quickly and easily.
- Rainbow tables can be reused for multiple attacks on different systems, as long as the hashes being used are the same.
Disadvantages:
- Rainbow tables can be quite large and require significant amounts of storage space, making them less practical for attacking systems with more complex passwords or a large number of users.
- Salted hashes can make rainbow table attacks much more difficult or even impossible, as each salt requires its own rainbow table to be created.
- The use of stronger and longer passwords can also make rainbow table attacks more difficult or even impractical, as the number of possible passwords increases exponentially.
🔹Defense against Rainbow Table Attacks
- Salted hashes: Adding a unique salt to each password before hashing can make it much more difficult for an attacker to use a precomputed rainbow table attack. A salt is a random string of characters that is added to the password before hashing.
- Stronger passwords: The use of strong, complex passwords that are not easily guessed can also make rainbow table attacks less effective. Longer passwords with a mix of uppercase and lowercase letters, numbers, and special characters are harder to crack.
- Hashing algorithms: Choosing a strong hashing algorithm, such as SHA-256 or SHA-3, can make rainbow table attacks more difficult, as these algorithms are designed to be resistant to precomputed attacks.
- Two-factor authentication: Implementing two-factor authentication can also help prevent rainbow table attacks, as an attacker would need to obtain both the password and the second factor (such as a code sent to a phone) to gain access.
- Regular password updates: Regularly updating passwords can help protect against rainbow table attacks, as any precomputed tables that an attacker may have become outdated and no longer useful.
Best 4 Tools for Rainbow Table Attack
- Rainbow Tables – These are a type of password database that can be used to store passwords in a variety of formats. They can be downloaded and used free of charge.
- Hashcat – This is a software tool that can be used to crack passwords. It can be downloaded and used for free.
- John the Ripper – This is a software tool that can be used to crack passwords. It can be downloaded and used for free.
- Cain & Abel – This is a password cracking tool that can be used to crack passwords. It can be downloaded and used for free.
This Post Create By : Hacker Alex
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