When is a domain computer account scheduled to change the password

active-directorypassword

I understand domain-joined computers have machine accounts in AD and these accounts have passwords that expire (apparently every 30 days by default) and those passwords are automatically changed without user intervention.

Given that this is known to cause issues when restoring snapshots of domain-joined virtual machines, is it possible to query the domain-joined computer or AD to determine when the machine account password is next scheduled to be changed?

Best Answer

It is possible to query the domain for this, the script below will tell you when a particular machine's domain password was last reset.

'Replace "yourdom.com" with your domain name.
DomainName = "yourdom.com"

querymachine = UCase(inputbox("Enter full machine name"))
lngBias = 2

'****************Setup Log file******************************************************

Set fso = CreateObject("Scripting.FileSystemObject")
'The 8 in this line will append to an existing file, replace with a 2 to override
set txtStream = fso.OpenTextFile("System.txt", 8, True)
txtStream.WriteLine "Ran on " & Date & " *******************************"

'****************Setup ADSI connection and populate ADSI Collection******************

Set objADOconnADSI = CreateObject("ADODB.Connection")
objADOconnADSI.Open "Provider=ADsDSOObject;"
Set objCommandADSI = CreateObject("ADODB.Command")
objCommandADSI.ActiveConnection = objADOconnADSI
'there is a 1000 object default if these next 2 lines are omited.
objCommandADSI.Properties("Size Limit")= 100000
objCommandADSI.Properties("Page Size")= 100000
objCommandADSI.Properties("Sort on") = "sAMAccountName"
objCommandADSI.CommandText = "<LDAP://" & DomainName & ">;(objectClass=computer);sAMAccountName,pwdLastSet,name,distinguishedname,operatingSystem;subtree"
Set objRSADSI = objCommandADSI.Execute

'Loop through record set and compare machine name*************************************

do while NOT objRSADSI.EOF
    if not isnull(objRSADSI.Fields("distinguishedname")) and objRSADSI.Fields("distinguishedname") <> "" then
    objDate = objRSADSI.Fields("PwdLastSet")
    'Go to function to make sense of the PwdLastSet value from AD for the machine account.
    dtmPwdLastSet = Integer8Date(objDate, lngBias)
    'calculate the current age of the password.
    DiffADate = DateDiff("d", dtmPwdLastSet, Now)

    'Is the machine the one we're looking for?
        if UCase(objRSADSI.Fields("name")) = querymachine then
        txtStream.WriteLine objRSADSI.Fields("name") & ";" & dtmPwdLastSet & ";" & DiffADate & ";" & objRSADSI.Fields("operatingSystem") 
        wscript.echo objRSADSI.Fields("name") & ", Last set: " & dtmPwdLastSet & ", Days since last change: " & DiffADate
        end if
    end if
objRSADSI.MoveNext
loop
wscript.echo "Done!"



Function Integer8Date(objDate, lngBias)
' Function to convert Integer8 (64-bit) value to a date, adjusted for
' local time zone bias.
Dim lngAdjust, lngDate, lngHigh, lngLow
lngAdjust = lngBias
lngHigh = objDate.HighPart
lngLow = objdate.LowPart
' Account for bug in IADslargeInteger property methods.
If lngLow < 0 Then
lngHigh = lngHigh + 1
End If
If (lngHigh = 0) And (lngLow = 0) Then
lngAdjust = 0
End If
lngDate = #1/1/1601# + (((lngHigh * (2 ^ 32)) _
+ lngLow) / 600000000 - lngAdjust) / 1440
Integer8Date = CDate(lngDate)
End Function

(I'd love to give credit for the above script but it's been handed around from person to person and modified in various ways, I have no idea where it originally came from)

Save this as something like MachinePasswordDate.vbs, doubleclicking the file in Windows should pop up a box you can put a machine name into, which should then query the domain and tell you when that machine's password was last changed.

If you're regularly restoring virtual machine snapshots it might be worth having a look at the security policies on those machines before you save off an image. You can change the machine password reset interval up to 999 days quite easily, assuming your domain GPOs won't override it, and your security policy allows this sort of thing:

Click Start, click Run, type Gpedit.msc, and then press ENTER.

Expand Local Computer Policy, Computer Configuration, expand Windows Settings, expand Security Settings, expand Local Policies, and then expand Security Options.

Configure the following settings:

  • Domain Member: Disable machine account password changes (Enabled)

  • Domain Member: Maximum machine account password age (999 days)

  • Domain Controller: Refuse machine account password changes (Enabled)

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