Passwords that contain only alphanumeric characters are easy to compromise by using publicly available tools. To prevent this, passwords should contain additional characters and meet complexity requirements. The following table lists the actual and effective default policy values. Default values are also listed on the policy's property page. This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.
Passwords that contain only alphanumeric characters are easy to discover with several publicly available tools. Configure the Passwords must meet complexity requirements policy setting to Enabled and advise users to use a variety of characters in their passwords. When combined with a Minimum password length of 8, this policy setting ensures that the number of different possibilities for a single password is so great that it's difficult but possible for a brute force attack to succeed.
If the Minimum password length policy setting is increased, the average amount of time necessary for a successful attack also increases. If the default configuration for password complexity is kept, more Help Desk calls for locked-out accounts could occur because users might not be used to passwords that contain non-alphabetical characters, or they might have problems entering passwords that contain accented characters or symbols on keyboards with different layouts.
However, all users should be able to follow the complexity requirement with minimal difficulty. If your organization has more stringent security requirements, you can create a custom version of the Passfilt. For example, a custom password filter might require the use of non-upper-row symbols. Upper-row symbols are those symbols that require you to press and hold the SHIFT key and then press any of the keys on the number row of the keyboard, from 1 through 9 and 0.
A custom password filter might also perform a dictionary check to verify that the proposed password doesn't contain common dictionary words or fragments. However, such stringent password requirements might result in more Help Desk requests. Alternatively, your organization could consider a requirement for all administrator passwords to use ALT characters in the — range.
ALT characters outside of this range can represent standard alphanumeric characters that wouldn't add more complexity to the password. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services.
Today, every system, device, account we need daily has its own password-creation rules, and it is becoming difficult maybe impossible to keep track of all access keys. Writing down passwords, re-using the same one for all systems, using easy-to-remember words or phrases or creating shorter access keys are problems that are a direct consequence of the overload of passwords we are all ask to use on a regular basis. With too many keywords to remember, people often choose weaker passwords that are less secure, online and offline.
Weak and insecure passwords are a security concern and a gateway to breaches that can affect more than just the targeted users. It is important to create keys that strike the right balance between being easy to remember and hard for others intruders or impostors to guess, crack or hack. The problem is that a good number of organizations rely solely on a password-based authentication and have not opted for more secure authentication systems e.
Considerations on password length and complexity are key in the quest for the ideal password. Complexity is often seen as an important aspect of a secure password. A random combination of alphanumerical characters and symbols intuitively seems as the best defense against cracking. Are they really effective against all attacks though? Probably not. Complex passwords, often tend to be shorter than passphrases, for example, and a brute-force attack with tools that quickly try all possible combinations of keys until they get it right might easily break them as the shorter the password, the smallest the number of possible combinations.
Brute-force attacks, thanks to the higher computing power of new machines as well as predictability of certain users-chosen character combinations are becoming particularly effective.
Due to the complexity of remembering sequences of random numbers, in fact, users often choose predictable sequences made of consecutive numbers and repetitions , for example or adjacent keyboard keys qwerty, zxc, etc…. Users could also engage in a number of other risky behaviors, like writing passwords down or reducing the number of characters used.
When a user is able to memorize such passwords, they also tend to use them consistently across all systems. So is a long password the way to go? Lengthy passwords are often associated with an increase in password entropy, which basically is the measure of how much uncertainty there is in a key.
An increase in entropy is seen as directly proportional to password strength. Therefore, a lengthy list of easy-to-remember words or a passphrase could be actually more secure than a shorter list of random characters. Lengthy passwords made of actual words are definitely easier to remember and could help users manage them in more secure way. Problems could arise, however, if users choose words that are too related to each other or too personal; this would open the door for dictionary-based passwords tools to guess the correct sequence even in presence of a larger amount of possible combinations.
Using something memorable or familiar family, pet or street name even in a password of adequate length and complexity is not practical as it makes it quite vulnerable for discovery by penetrators.
An interesting Microsoft TechNet blog article shows how, by looking at the formula to calculate bits of entropy the measure in bits of how difficult it is to hack a password , the role of length is emphasized.
This is a great and wholly intended effect of a password length constraint. The problem with a lack of constraints is that people will use a very small set of all possible passwords, which invariably includes passwords that are incredibly easy to guess. In the analysis of over one million leaked passwords, it was found that That does not take a computer very long to crack.
To beef up security, we begin to add character constraints. But, in doing so, we decrease the number of possible passwords; both good and bad. Just by requiring both uppercase and lowercase letters, more than 15 percent of all possible 8-character combinations have been eliminated as possible passwords.
But you cannot use it. Superior passwords that cannot be used are acceptable collateral damage in the battle for better security. This clearly is not a battle for lower cholesterol. If a password must be exactly eight characters long and contain at least one lower case letter, at least one uppercase letter and at least one symbol, we are getting close to one-in-five combinations of 8 characters that are not allowable as passwords. Still, the effect of constraints on 12 and 16 character passwords is negligible.
But that is all about to change… you can count on it. Are you required to use a password that is at least eight characters long, has lower and uppercase letters, number and symbols? Just requiring a number to be part of a password removes over 40 percent of 8-character combinations from the pool of possible passwords. Even though you can use lowercase and uppercase letters, and you can use symbols, if one of the characters in your password must be a number then there are far fewer great passwords that you can use.
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