Attributes for AD Users : lastLogon

The Active Directory attribute lastLogon shows the exact timestamp of the user's last successful domain authentication on the regarding domain controller. It doesn't matter here how the user performed this logon operation - interactive, network, passed-through from a radius service or another kerberos realm. If the user never did logon to the DC, the value of lastLogon is zero.

lastLogon

LDAP Name	lastLogon
Data type	Integer8 (64 bit signed numeric)
Multivalue (Array)	No
System Flags	0x11
Search Flags	0x0
In Global Catalog?	No
Attribute ID	1.2.840.113556.1.4.52
AD DB attribute name	Last-Logon
ADSI datatype	10 - LargeInteger
LDAP syntax	1.2.840.113556.1.4.906 - Microsoft Large Integer
Used in ...	> W2K
Schema Doku	Microsoft - MSDN

Please note that this value is NOT replicated between domain controllers - if you want to know the exact last logon time for an account in a domain with more than one domain controllers, you have to check this value on all domain controllers! In Windows 2003 Active Directory, Microsoft introduced another user attribute named lastLogonTimestamp. This attribute is replicated to other DCs, but only after two weeks (minus a random percentage of 5 days), so it is suitable to locate inactive accounts which did not logon to the domain for a long time.

The lastLogon value is a Microsoft Large Integer, these are signed numeric values of 8 Byte (64 bit) - those are often called Integer8 values for this reason:

Minimum value:
-9223372036854775808 (-2^63) or
hex 0x8000000000000000

Maximum value:

9223372036854775807 (2^63 - 1) or
hex 0x7FFFFFFFFFFFFFFF

There is another article in the SelfADSI Tutorial about the Microsoft Integer8 values which represent date and time or time intervals.

The value stored in the lastLogon attribute represents the date and time of the account logon, expressed in 100-nanosecond steps since 12:00 AM, January 1, 1601.

By the way, this is a specification which is also used in the Microsoft FileTime structure. Additionally, it is important to know that an Active Directory domain controller stores the date and time always in the UTC time format (Universal Coordinated Time) - this is (almost) the former Greenwich Meantime (GMT). So if your systems are for example in Pacific Standard Time (PST, which is GMT-8), so you have to recalculate the Integer8 attribute values if you want to know the date and times in your local time.

If you want to read the lastLogon attribute of a certain user, you first have to handle the returned Large Integer which is divided into two 32bit parts: The HighPart and the LowPart. These parts are accessible in the ADSI interface for this datatype. But: You always have to use a leading 'Set' statement when reading a Large Integer/Integer8 attribute in an ADSI script. Otherwise you can't access the ADSI interface properties 'Highpart' and 'Lowpart'.

So here is the script code to convert an Integer8 into a date and time, including the local time zone adjustment (we take the time abbreviation from UTC from the registry):

'you have to use a distinguished name of an object from you own environment here!
Set obj = GetObject("LDAP://cn=Administrator,cn=Users,dc=cerrotorre,dc=de")

set llValue = obj.Get("lastLogon")
'remember: use 'SET' to create an object!
WScript.Echo LargeIntegerToDate(llValue)

Function LargeIntegerToDate(value)
'takes Microsoft LargeInteger value (Integer8) and returns according the date and time

    'first determine the local time from the timezone bias in the registry
    Set sho = CreateObject("Wscript.Shell")
    timeShiftValue = sho.RegRead("HKLM\System\CurrentControlSet\Control\TimeZoneInformation\ActiveTimeBias")
    If IsArray(timeShiftValue) Then
        timeShift = 0
        For i = 0 To UBound(timeShiftValue)
            timeShift = timeShift + (timeShiftValue(i) * 256^i)
        Next
    Else
        timeShift = timeShiftValue
    End If

    'get the large integer into two long values (high part and low part)
    i8High = value.HighPart
    i8Low = value.LowPart
    If (i8Low < 0) Then
        i8High = i8High + 1
    End If

    'calculate the date and time: 100-nanosecond-steps since 12:00 AM, 1/1/1601
    If (i8High = 0) And (i8Low = 0) Then
        LargeIntegerToDate = #1/1/1601#
    Else
        LargeIntegerToDate = #1/1/1601# + (((i8High * 2^32) + i8Low)/600000000 - timeShift)/1440
    End If
End Function

Here comes another script where you need to convert a date and time value to the according Integer8 - we want to find all users which logged on to a certain domain controller in the last week. To build a correct LDAP filter, we need the Large Integer value for the date and time one week ago.... If you don't know exactly how the script searches for the objects - there is a detailed article here in the SelfADSI Tutorial which explains the LDAP search with ADO techniques.

'you have to use names and credentials of your own environment here!
serverName = "nadrash.cerrotorre.de"
baseStr = "dc=cerrotorre,dc=de"
userName = "philipp@cerrotorre.de"
userPass = "secret"

'get the date and time of one week ago, DateAdd is a standard vbscript function, we could also calculate last month, year etc.
lastWeek = DateAdd("ww", -1, Now)

'get the Integer8 value for the regarding date an time...
lastWeekValue = DateToLargeIntegerString(lastWeek)

'show the both values:
WScript.Echo "Timestamp of one week ago: " & lastWeek & " => " & lastWeekValue

'now get a filter of all user accounts which logged on in the last week
filterStr = "(&(objectclass=user)(lastLogon>=" & lastWeekValue & "))"

'do the search!
Set ado = CreateObject("ADODB.Connection")              'create new ADO connection
ado.Provider = "ADSDSOObject"                           'use the ADSI interface
ado.Properties("User ID") = userName                    'pass credentials - omit these 2 lines to use your current credentials!
ado.Properties("Password") = userPass
ado.Properties("Encrypt Password") = True
ado.Open "ADS-Search"                                   'use any name for the connection

Set adoCmd = CreateObject("ADODB.Command")              'create new ADO command
adoCmd.ActiveConnection = ado                           'assignment to an existing ADO connection
adoCmd.Properties("Page Size") = 1000                   'set the Paged Results value to 1000 (AD standard)
adoCmd.Properties("Cache Results") = True
adoCmd.CommandText = "<LDAP://" & serverName & "/" & baseStr & ">;" & filterStr & ";distinguishedName;subtree"

Set objectList = adoCmd.Execute                         'perform search
While Not objectList.EOF
    WScript.Echo objectList.Fields("distinguishedName") 'output: distinguishedName of these objects
    objectList.MoveNext                                 'jump to the next search result entry
Wend

Function DateToLargeIntegerString(value)
'takes a date/time and returns the according Microsoft LargeInteger value (Intger8)

    'first determine the local time from the timezone bias in the registry
    Set sho = CreateObject("Wscript.Shell")
    timeShiftValue = sho.RegRead("HKLM\System\CurrentControlSet\Control\TimeZoneInformation\ActiveTimeBias")
    If IsArray(timeShiftValue) Then
        timeShift = 0
        For i = 0 To UBound(timeShiftValue)
            timeShift = timeShift + (timeShiftValue(i) * 256^i)
        Next
    Else
        timeShift = timeShiftValue
    End If

    'adjust the local time to UTC
    value = DateAdd("n", timeShift, value)

    'how much seconds since 1601 are in the time?
    secs = DateDiff("s", #1/1/1601#, value)

    'convert it to 100-nanosecond steps
    DateToLargeIntegerString = CStr(secs) & "0000000"
End Function

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