Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f3071f320b10eec4…

MALICIOUS

Office (OLE)

328.1 KB Created: 2019-02-20 07:25:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: b7cbb014b58bc0ea3c6fc5e02460ecf7 SHA-1: fcf031f8acc64508c2c5e57adb6fe943c7059754 SHA-256: f3071f320b10eec4ce05b88be0102ac3c44d22bb405525d7ea7eed5829f4b4ee
82 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The presence of legacy WordBasic auto-exec markers and an Excel 4.0 macro sheet strongly indicates the file is designed to run malicious macros. The large slack space in the OLE structure is also a common characteristic of packed or obfuscated malicious documents. While no specific payload or C2 communication was directly observed, the file's structure points to an attempt to execute arbitrary code.

Heuristics 4

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 336,000 bytes but its declared streams total only 149,809 bytes — 186,191 bytes (55%) 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.
  • 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)

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