MTM stands for “Memory-time trade-off” is a type of attack that is used to crack password-protected systems by attempting to guess the password. This attack involves the use of a precomputed table, also known as a “rainbow table,” which contains the results of pre-hashed password values. The attacker can then use this table to quickly look up the corresponding plaintext password for a given hashed value, thereby bypassing the need to repeatedly hash the same password guesses.
One example of an MTM attack is the use of a rainbow table to crack the Windows LAN Manager (LM) hash. LM hashing is a legacy hashing algorithm used by Windows to store user passwords. The algorithm is considered weak because it only uses the first 7 characters of a password and converts them to uppercase. This means that all passwords shorter than 7 characters are padded with null bytes, and all passwords longer than 7 characters are truncated. This makes it easier for an attacker to guess the password and crack the hash.
In order to perform an MTM attack, the attacker first needs to obtain the hashed password value, which can be done by various means such as cracking the hash using a dictionary attack, or by using a tool such as Cain and Abel to extract the hash from the system.
Once the attacker has the hashed password, they can then use a precomputed rainbow table to look up the corresponding plaintext password. One example of a tool that can be used to generate and use rainbow tables is Ophcrack.
In order to protect against MTM attacks, it is important to use strong and unique passwords, and to use a hashing algorithm that is considered secure. Additionally, using two-factor authentication (2FA) can also help to protect against MTM attacks, as it requires a second form of authentication in addition to the password.
In summary, Memory-Time trade-off (MTM) is a type of attack that is used to crack password-protected systems by attempting to guess the password using precomputed table known as “rainbow table” the attacker can then use this table to quickly look up the corresponding plaintext password for a given hashed value, thereby bypassing the need to repeatedly hash the same password guesses. To protect against MTM attacks, it is important to use strong and unique passwords, and to use a hashing algorithm that is considered secure. Additionally, using two-factor authentication (2FA) can also help to protect against MTM attacks, as it requires a second form of authentication in addition to the password.