Vulnerability Discussion

Outdated or unused accounts provide penetration points that may go undetected. Inactive accounts must be deleted if no longer necessary or, if still required, disabled until needed.

Check

Open "Windows PowerShell".

Domain Controllers:

Enter "Search-ADAccount -AccountInactive -UsersOnly -TimeSpan 35.00:00:00"

This will return accounts that have not been logged on to for 35 days, along with various attributes such as the Enabled status and LastLogonDate.

Member servers and standalone or nondomain-joined systems:

Copy or enter the lines below to the PowerShell window and enter. (Entering twice may be required. Do not include the quotes at the beginning and end of the query.)

"([ADSI]('WinNT://{0}' -f $env:COMPUTERNAME)).Children | Where { $_.SchemaClassName -eq 'user' } | ForEach {
$user = ([ADSI]$_.Path)
$lastLogin = $user.Properties.LastLogin.Value
$enabled = ($user.Properties.UserFlags.Value -band 0x2) -ne 0x2
if ($lastLogin -eq $null) {
$lastLogin = 'Never'
}
Write-Host $user.Name $lastLogin $enabled
}"

This will return a list of local accounts with the account name, last logon, and if the account is enabled (True/False).
For example: User1 10/31/2015 5:49:56 AM True

Review the list of accounts returned by the above queries to determine the finding validity for each account reported.

Exclude the following accounts:

- Built-in administrator account (Renamed, SID ending in 500)
- Built-in guest account (Renamed, Disabled, SID ending in 501)
- Application accounts

If any enabled accounts have not been logged on to within the past 35 days, this is a finding.

Inactive accounts that have been reviewed and deemed to be required must be documented with the Information System Security Officer (ISSO).

Fix

Regularly review accounts to determine if they are still active. Remove or disable accounts that have not been used in the last 35 days.