A security administrator must implement all requirements in the following corporate policy: Passwords
shall be protected against offline password brute force attacks. Passwords shall be protected against
online password brute force attacks. Which of the following technical controls must be implemented to
enforce the corporate policy? (Select THREE).

A.
Account lockout

B.
Account expirationC. Screen locks

D.
Password complexity

E.
Minimum password lifetime

F.
Minimum password length

Explanation:
A brute force attack is a trial-and-error method used to obtain information such as a user password or
personal identification number (PIN). In a brute force attack, automated software is used to generate a
large number of consecutive guesses as to the value of the desired data. Brute force attacks may be used
by criminals to crack encrypted data, or by security analysts to test an organization’s network security.
A brute force attack may also be referred to as brute force cracking.
For example, a form of brute force attack known as a dictionary attack might try all the words in a
dictionary. Other forms of brute force attack might try commonly-used passwords or combinations of
letters and numbers.
The best defense against brute force attacks strong passwords. The following password policies will
ensure that users have strong (difficult to guess) passwords:
F: Minimum password length. This policy specifies the minimum number of characters a password should
have. For example: a minimum password length of 8 characters is regarded as good security practice.
D: Password complexity determines what characters a password should include. For example, you could
require a password to contain uppercase and lowercase letters and numbers. This will ensure that
passwords don’t consist of dictionary words which are easy to crack using brute force techniques.
A: Account lockout policy: This policy ensures that a user account is locked after a number of incorrect
password entries. For example, you could specify that if a wrong password is entered three times, the
account will be locked for a period of time or indefinitely until the account is unlocked by an
administrator.
Incorrect Answers:B: Account expiration settings determine when an account will expire. This is usually a time or date. An
account configured with an expiration date will not prevent an attacker trying to brute force a password
as the attacker could make as many attempts as he wants until the time or date of the account
expiration.
C: A screen lock will cause the screen of a computer or mobile device to lock after a period of inactivity. It
is not used to prevent brute force attacks.
E: Password history determines the number of previous passwords that cannot be used when a user
changes his password. For example, a password history value of 5 would disallow a user from changing his
password to any of his previous 5 passwords.
When a user is forced to change his password due to a maximum password age period expiring, he could
change his password to a previously used password. Or if a password history value of 5 is configured, the
user could change his password six times to cycle back round to the original password. This is where the
minimum password age (minimum password lifetime) comes in. This is the period that a password must
be used for. For example, a minimum password age of 30 would determine that when a user changes his
password, he must continue to use the same password for at least 30 days. A minimum password age
would not protect against brute force attacks.

https://technet.microsoft.com/enus/library/cc757692%28v=ws.10%29.aspx#w2k3tr_sepol_accou_set_kuwh