## Question

How password strength is determined for Plesk 11.5 and 12.0.18 ?

## Theory

Passwords strengths is a sum of the following criterias. Where all characters are verified against rule set, for every match it adds some scores/weights defined for different cases.

Here is rules are applied to validate password in Plesk 11.5 and 12:

If a password is 4 or less symbols in length, it gains 3 scores.

If the length is between 5 and 7, then it gains 6 scores.

If the length is between 8 and 15, then it gains 12 scores.

If the length is 16 or more, then it gains 18 scores.

If password contains at least one lower case letter from '

`a`

' to '`z`

', then it give us 1 score.If there is at least one upper case letter from

`'A'`

to`'Z'`

, then it brings 5 scores.If there is at least one number, then it brings 5 scores.

If there is at least three numbers, then it brings 5 scores.

If there is at least one special character from this list (without quotes): "

`!, @, #, $, %, ^, &, *, ?, _, ~`

", then it brings 5 scores.If there is at least two special characters from the list above, then it brings 5 scores.

If there is both upper and lower case, then it brings 2 scores.

If both letters and numbers, then it brings 2 scores.

If there is combination of letters and numbers and special characters, then it will give us 2 scores.

If the sum of score more than 16, the password is

`Very Weak`

.If the sum of scores between 15 and 24, then it is

`Weak password`

If the sum of scores between 25 and 34, then it is

`Medium password`

.If the sum of scores between 35 and 44, then it is

`Strong password`

.- If the sum of score is more than 45, it is
`Very Strong`

.

## Example

Let's look how it works on the password "`P@ssw0rd`

"

- Length between 8 and 15 (+12)
- At least one lower case letter (+1)
- At least one lower case letter uppercase (+5)
- At least one number (+5)
- At least one special character (+5)
- Have both upper and lower case (+2)
- Have both letters and numbers (+2)
- Have letters, numbers and special characters (+2)

Overall score is 34, which is less than 35. Verdict is Medium