Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3efafa30055dbac5…

MALICIOUS

Office (OLE)

256.4 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 9bfb40779a465d8426aa37e81b7717f1 SHA-1: b65a72133179a1702089b89331af783524226895 SHA-256: 3efafa30055dbac5765c95d77873a5c3793c642e431f3558c4c6d1a17671a746
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

The sample is an OLE Excel file 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 to execute malicious code. No document body or scripts were extracted, limiting further analysis of the 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 262,545 bytes but its declared streams total only 24,565 bytes — 237,980 bytes (91%) 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).