Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b4d00a77fdffe560…

MALICIOUS

Office (OLE)

206.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 510a8192db8ab2cfe1b2cef2d66e8857 SHA-1: 6a48c0367e656aa9a83c1052f5729fdb8826f24e SHA-256: b4d00a77fdffe560f401dcbb13415c5dba147919af97ee019bead5425d613884
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File

The sample is an Excel OLE document exhibiting a significant slack space anomaly and a critical heuristic firing for CVE-2009-3129, indicating an exploit within the FEATHEADER record. This suggests the file is designed to leverage this vulnerability upon opening. While no document body or scripts were extracted, the exploit itself is the primary indicator of malicious intent, likely leading to the download or execution of a secondary payload.

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=22, isf=4, cbHdrData=4). 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 210,981 bytes but its declared streams total only 24,565 bytes — 186,416 bytes (88%) 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).