Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 5460799cc009019c…

MALICIOUS

Office (OLE) / .XLS

107.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 3ec79d113a0e651cfa61a25489e58664 SHA-1: 6fdedb8c96290fb155367897703f44bca22ee2e9 SHA-256: 5460799cc009019c7d388a85722c610e7caed543e308f231006130313d42ecb0
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1204.002 Malicious File: User Execution

The file is an Excel spreadsheet that triggers the CVE-2009-3129 vulnerability due to a FEATHEADER record overflow. This indicates the file is designed to exploit this specific Excel flaw, likely to execute arbitrary code. No document body or scripts were extracted, but the critical heuristic firing strongly suggests a 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 109,592 bytes but its declared streams total only 24,565 bytes — 85,027 bytes (78%) 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).