Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fec7b19f14b01332…

MALICIOUS

Office (OLE)

330.9 KB Created: 2019-02-20 19:52:00 Authoring application: Microsoft Office Word First seen: 2019-08-04
MD5: a5bcccfca47c2d5d114e9ca8539f656a SHA-1: da34b47a26b2a4d5a8a261176e792ac999a3f1d5 SHA-256: fec7b19f14b01332828e3c1c8fb6ef6d7991228d4ec549ce830ea1a74b622d28
90 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The presence of legacy WordBasic auto-execution markers ('autoopen') and an Excel 4.0 macro sheet indicates the file is designed to run embedded code. The large slack space in the OLE structure is also suspicious. While no specific malicious script was found, these indicators point to a macro-based execution attempt.

Heuristics 5

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 338,816 bytes but its declared streams total only 149,691 bytes — 189,125 bytes (56%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 282 bytes
SHA-256: 6eb189bbe0fcdc9fa4b8538ee735a88c773eee6768b5636fc6f300f7e6ee644b
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "l508_39_"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

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