Rainbow Table Attack

Rainbow Table Attack Definition

In a substantiation attack known as a rainbow table attack, the attacker compiles a list of cryptographic hashes of known passwords. Instead of maintaining passwords in plaintext, authentication systems often save them in a hashed format, which is calculated using a cryptographic strategy. A user's password is hashed and compared to their own stored hash during authentication.

Although these hashing techniques are a vast improvement over plaintext lists, particularly older versions, they suffer from a critical weakness. The hashing function assigns a value to each character in the password, producing a string of random alphanumeric characters. An attacker can generate a rainbow table, which contains all possible hashes, in advance. When an attacker has a list of hashed passwords, he or she can use the password rainbow table to quickly and easily determine the related keys.

Since the approach requires less computing power than a brute force attack, but rainbow tables demand a large amount of storage space, it is an example of the time/memory trade-off.

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How Do Rainbow Table Attacks Work?

A series of hashing and reducing processes form the backbone of rainbow tables. The reduction function reverses the process, connecting hash values to their corresponding plaintexts.

There are four stages to this procedure.

1. Generation

The rainbow table works by first taking a list of possible passwords and hashing them all with the same function. The rainbow table stores the hashes and the plaintext passwords that correlate to them.

2. Reduction

In order to create a new set of hashes, a reduction function is applied to the hashes already present in the rainbow table. Using a reduction function, each hash is remapped to a new value that is then utilized as input to the next stage of the process. To generate a string of hashes, this procedure is done many times.

3. Lookup

A rainbow table is a tool used by hackers to decipher encrypted passwords from a set of hashes. Starting with the last hash in each chain, they work their way back through the rainbow table's hashes until they locate one that matches the target hash.

4. Cracking

The plaintext password that matches the detected hash value is the one that was used to generate the target hash. The hacker can now use this vulnerability in the authentication procedure to get access to a protected resource.

Table Creation

A string's hash is reduced to a new string, which is reduced again. Let's produce a table of the most frequent password, 12345678, using the MD5 hash function on the first 8 characters:

First, we run the string via the md5 hash algorithm.

hashMD5(12345678) = 25d55ad283aa400af464c76d713c07ad

Only the first 8 letters are used to lower the hash. Afterward, we rehash it.

hashMD5(25d55ad2) = 5c41c6b3958e798662d8853ece970f70

Repeat until enough output chain hashes. One chain from the initial plain text to the last hash.

We put enough chains on a table.

Password Cracking

The catalogue is verified for the hashed password. If so, start hashing from the inception. After finding a match, the authentication is broken.

Pros And Cons of Rainbow Table Attack

The perks of using rainbow tables are as follows:

• They make despotism attacks and dictionary attacks obsolete as a means of breaking passwords.
• All the values in a rainbow table should already be computed, so the process is reduced to a search and comparison.
• There's no requirement to know the password exactly. As long as the hash values are the same, verification is achievable. 

The following are some of the imperfections of rainbow tables:

• They need a lot of space to store their data so they can launch their assaults in a judicious length of time.
• It's much harder for an attacker to succeed if the hash they're trying to crack isn't already in the table.
• The introduction of contemporary cryptographic hash actions, principally salted keywords, has greatly reduced the prevalence of rainbow attacks.

Real-World Examples of Rainbow Table Attacks

Hackers can perform rainbow table attacks by gaining unsanctioned access to hashes in a number of ways:

• They locate a business or website that has inadequate security measures in place, such as weak hashing of login information. After breaking into the database, the hacker will steal the hashes and try to crack them using a rainbow table.
• Hackers find holes in a company's Active Directory and use it to retrieve the hashes of users' passwords. Once an attacker gets the hashes, all they need to do is launch a rainbow table assault.
• Phishing attacks are another method for gaining access to users' login details. Unless the hashes are salted, you have no recourse once the PINs have been stolen and hashed.

How Do I Protect Myself from Rainbow Table Attacks?

Managers of computer networks should implement the following safeguards to stop attacks utilizing rainbow tables:

• Salting

Passwords are encrypted after being supplemented with a random string of characters using this method. Assuming a text string has a fixed hash value, rainbow table assaults succeed; nevertheless, the created characters alter the original hash value.

• Using biometrics for verification

Since biometric keywords validate the user's recognition, they are immune to rainbow table attacks. They are not like a password in that they are put in, and they are personal to each user.

• Key elongation

To lengthen the computation time obligatory for an attack, a hash function is repeatedly applied to the password, salt, and intervening hash result.

• Inspecting the Servers

Security software on servers can identify intrusions even before potential attackers locate password registries.

• Safe hashing algorithms

Companies should stop employing insecure hashing techniques like Secure Hash Algorithm 1 and the message-digest algorithm. The more secure SHA-3 hashing algorithm should be considered instead.

The Future of Rainbow Tables Attacks - How Dangerous Is It Now?

Since the use of the salting strategy, both the frequency and severity of rainbow table attacks have dropped significantly. Salted hashes are used by several popular operating systems and software distributions.

Apple's macOS password manager, Keychain, also makes use of salt. Despite Windows' lack of salt, hashes can still be encrypted with the Syskey program. Nonetheless, Windows hosts the potential for rainbow table assaults for eight- and nine-character.

In recent years, GPU-based brute force assaults have surpassed rainbow table cyber security attacks in terms of practicality. In GPU brute-force attacks, the graphics processing unit of a computer is used to try guessing passwords, rather than the CPU.

Rainbow table attacks are slower, less scalable, and limited to the hash and type of a given password compared to other methods.