Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 742d669cc50d4b69…

MALICIOUS

Office (OLE)

226.7 KB First seen: 2015-09-20
MD5: 4a19f19720837a9a41cb6f7684e508d2 SHA-1: d60ca8c258dd3697a06d1924e4f964bf2381eb3c SHA-256: 742d669cc50d4b697764e657cadf56236816837c9f7b19103773b0659d7c27af
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV with the signature Doc.Dropper.Agent-6966177-0. Static analysis reveals a critical vulnerability exploit for CVE-2009-3129 in Excel, indicating it's designed for client-side execution. Additionally, the file contains an appended executable payload, suggesting its primary purpose is to drop and run additional malware.

Heuristics 4

  • 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.
  • ClamAV: Doc.Dropper.Agent-6966177-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6966177-0
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 232,168 bytes but its declared streams total only 34,044 bytes — 198,124 bytes (85%) 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.