Here is a starter in VBA. Alt+F11, VBA Editor, New Module, paste the following Sub.
Then in Acad/Tools/Macros/Run
This SUb opens all dwgs in a directory, finds block "title" and closes the dwg.
To modify an attribute, you have to see the Example_getAttributes in VBA Editor menu and include it within the while loop here.
'Option Explicit
Sub BatchEditAttr()
On Error Resume Next
Dim whichblock As AcadBlock
MyDir = "D:\Tigrek\Temp\"
myPath = MyDir & "*.dwg"
'NextDWG = Dir("D:\Tigrek\Temp\*.dwg"

NextDWG = Dir(myPath)
Debug.Print NextDWG
While NextDWG <> ""
Debug.Print NextDWG
NextOpen = MyDir & NextDWG
ThisDrawing.Open (NextOpen)
Set whichblock = ThisDrawing.Blocks.Item("TITLE"

Debug.Print whichblock.Name
'To be added here
'Get atribute - see Example_GetAttributes in VBA editor help
'Modify Attribute
NextDWG = Dir
Wend
End Sub