Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 fc9224e80986ac15…

MALICIOUS

Office (OLE) / .XLS

77.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2026-05-10
MD5: 13b15741843264f444fa3ac6a5a4bf8e SHA-1: c45768936d2b265afc3dc0018ca8723aefb869c5 SHA-256: fc9224e80986ac15d76f4d40a9167f4daa1fab851dcd29f0b72b8c2721a24a58
100 Risk Score

Heuristics 2

  • CVE-2009-3129 — Excel FEATHEADER record overflow critical CVE exact CVE_2009_3129
    Workbook BIFF stream contains a FEATHEADER (Feature Header) record with anomalous size (record_size=23, isf=2, cbHdrData=4294967295). Legitimate FEATHEADER records are tiny (<100 bytes) and carry cbHdrData values that fit in the record body; the value here is the documented CVE-2009-3129 exploit primitive — cbHdrData drives a memcpy with attacker-controlled size, leading to memory corruption and code execution in Excel 2007/2003.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 79,320 bytes but its declared streams total only 24,565 bytes — 54,755 bytes (69%) 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).