Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f4434999f8d2faab…

MALICIOUS

Office (OLE)

153.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 2398034b49f31edc1a1a05e6b378f446 SHA-1: 866b442e24fa94615ef5a333fec151b6e97451b3 SHA-256: f4434999f8d2faabb70f9c7fe9fbb65248827c528db84471999b8b4ce621c6c4
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

The sample is an OLE Excel file that triggers a critical heuristic for CVE-2009-3129, indicating exploitation of a specific Excel vulnerability. The large slack space also suggests potential obfuscation or padding typical of malicious documents. Without a document body or scripts, the exact payload delivery mechanism is unclear, but the exploit itself is the primary indicator of malicious intent.

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 156,682 bytes but its declared streams total only 24,565 bytes — 132,117 bytes (84%) 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).