Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f11ad00897b37185…

MALICIOUS

Office (OLE)

29.5 KB Created: 1993-09-28 16:08:00 Authoring application: Microsoft Word for Windows 95 First seen: 2012-06-14
MD5: ab5850636df18b3b611f0f931a5aa379 SHA-1: adaa90b72bc2e067c2885850b00eefa9da112dc1 SHA-256: f11ad00897b37185e555fb3bf17ba28bef6de1b6481f55e4e5811d18b8d860a0
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The presence of legacy WordBasic auto-exec markers like 'AutoOpen' and critical heuristics related to OLE structure anomalies (slack space, empty streams, FAT chain loop) strongly suggest malicious intent. ClamAV detection as Win.Trojan.Th-1 further supports this. The embedded OLE object is a primary indicator of a potentially malicious macro-based document.

Heuristics 5

  • ClamAV: Win.Trojan.Th-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Th-1
  • Embedded Office document has suspicious static findings critical EMBEDDED_OFFICE_CHILD_STATIC_TRIAGE
    A CFB/OLE Office document was found inside another file type and its carved contents matched Office exploit or payload heuristics. This catches wrapped exploit documents where the top-level file routes to a PE, archive, or generic scanner instead of Office.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 21,760 bytes but its declared streams total only 0 bytes — 21,760 bytes (100%) 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.
  • CFB header with no readable streams medium OLE_PARSE_EMPTY_STREAMS
    The file begins with a valid OLE2/CFB header but exposes no directory streams. A non-empty compound document with an unreadable directory is anomalous — it is seen with truncated/corrupt files and, more importantly, with content deliberately shifted off byte boundaries to defeat parsers while the host application still recovers the object.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_office_off00002100.ole embedded-office Embedded OLE/CFB Office body inside ole container at offset 0x2100 21760 bytes
SHA-256: fe25d6373e99d8148b34047b9574f68de861da665cdeb840a8e4bc7436c6ea46