Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7bd3c625e07c4797…

MALICIOUS

Office (OLE)

236.2 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: bc794438966cc1082e2d613d214d805b SHA-1: 1f0694104e248de58f982ed4ed956490a62372d9 SHA-256: 7bd3c625e07c4797ad2dbf53198244e3d381d77c2a3c007c457536164edd3ed0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is identified as malicious due to multiple high-severity heuristic firings. Specifically, it exhibits an OLE slack anomaly and an appended executable payload, indicating a packed or obfuscated structure. The critical finding is the exploitation of CVE-2009-3129, a known vulnerability in Microsoft Excel related to FEATHEADER record overflow, which allows for arbitrary code execution.

Heuristics 3

  • 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 241,844 bytes but its declared streams total only 24,565 bytes — 217,279 bytes (90%) 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).
  • OLE file has appended executable-looking payload bytes high OLE_APPENDED_PAYLOAD
    OLE compound file contains a large high-entropy region beyond the declared major streams and that region includes shellcode, PE, or loader API markers. This is a payload-carrier signal, not a specific CVE attribution by itself.