Class: PasswordIsStrongValidator

Inherits:
ActiveModel::EachValidator
  • Object
show all
Defined in:
app/validators/password_is_strong_validator.rb

Overview

Validates that the password is strong.

Constant Summary collapse

COMMON_PASSWORDS =

Password that are used too often and will be easily guessed.

%w{
	password pass root admin metasploit
	msf 123456 qwerty abc123 letmein monkey link182 demo
	changeme test1234 rapid7
}

Instance Method Summary collapse

Instance Method Details

#contains_repetition?(password) ⇒ Boolean (private)

Password repetition (quite basic) -- no "aaaaaa" or "ababab" or "abcabc" or "abcdabcd" (but note that the user can use "aaaaaab" or something).

Parameters:

  • password (String)

Returns:

  • (Boolean) 


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# File 'app/validators/password_is_strong_validator.rb', line 53

def contains_repetition?(password)
  if password.scan(/./).uniq.size < 2
    return true
  end

  if (password.size % 2 == 0) and (password.scan(/../).uniq.size < 2)
    return true
  end

  if (password.size % 3 == 0) and (password.scan(/.../).uniq.size < 2)
    return true
  end

  if (password.size % 4 == 0) and (password.scan(/..../).uniq.size < 2)
    return true
  end

  false
end

#contains_username?(username, password) ⇒ false, true (private)

Whether username is in password (case-insensitively).

Returns:

  • (false) —

    if password is blank.

  • (false) —

    if username is blank.

  • (false) —

    unless username is in password.

  • (true) —

    if username is in password.



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# File 'app/validators/password_is_strong_validator.rb', line 79

def contains_username?(username, password)
  contains = false

  unless password.blank? or username.blank?
    escaped_username = Regexp.escape(username)
    username_regexp = Regexp.new(escaped_username, Regexp::IGNORECASE)

    if username_regexp.match(password)
      contains = true
    end
  end

  contains
end

#is_common_password?(password) ⇒ Boolean (private)

Whether password is in COMMON_PASSWORDS or a simple variation of a password in COMMON_PASSWORDS.

Parameters:

  • password (String)

Returns:

  • (Boolean) 


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# File 'app/validators/password_is_strong_validator.rb', line 98

def is_common_password?(password)
  COMMON_PASSWORDS.each do |pw|
    common_pw = [pw, pw + "!", pw + "1", pw + "12", pw + "123", pw + "1234"]
    if common_pw.include?(password.downcase)
      return true
    end
  end
  false
end

#is_simple?(password) ⇒ false, true (private)

Returns whether the password is simple.

Returns:

  • (false) —

    if password contains a letter, digit and special character.

  • (true) —

    otherwise



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# File 'app/validators/password_is_strong_validator.rb', line 112

def is_simple?(password)
  not (password =~ /[A-Za-z]/ and password =~ /[0-9]/ and password =~ /[\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x3a\x3b\x3c\x3d\x3e\x3f\x5b\x5c\x5d\x5e\x5f\x60\x7b\x7c\x7d\x7e]/)
end

#validate_each(record, attribute, value) ⇒ void

This method returns an undefined value.

Validates that value is a strong password. A password is strong if it meets the following rules:

  • SHOULD contain at least one letter.
  • SHOULD contain at least one digit.
  • SHOULD contain at least one special character.
  • SHOULD NOT contain record.username (case-insensitive).
  • SHOULD NOT be in COMMON_PASSWORDS.
  • SHOULD NOT repetitions.

Parameters:

  • record (#errors, #username, ActiveRecord::Base) —

    ActiveModel or ActiveRecord that supports #username method.

  • attribute (Symbol) —

    password attribute name.

  • value (String) —

    a password.



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# File 'app/validators/password_is_strong_validator.rb', line 26

def validate_each(record, attribute, value)
  return if value.blank?

  if is_simple?(value)
    record.errors[attribute] << 'must contain letters, numbers, and at least one special character'
  end

  if contains_username?(record.username, value)
    record.errors[attribute] << 'must not contain the username'
  end

  if is_common_password?(value)
    record.errors[attribute] << 'must not be a common password'
  end

  if contains_repetition?(value)
    record.errors[attribute] << 'must not be a predictable sequence of characters'
  end
end