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

Static analysis result for SHA-256 92d62ba375439ebf…

MALICIOUS

Office (OLE) / .XLS

154.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 34eba128caa21df52b7cec6ea1c80a91 SHA-1: dcd2ba6b02c6e27680037fa7fd8e8ecc0bdb0e31 SHA-256: 92d62ba375439ebf2577e0530de27dcdc1793c82953820bf5c5bba91aefb7b61
100 Risk Score

Malware Insights

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

The file is an Excel spreadsheet that exhibits a significant slack space anomaly, indicating potential obfuscation or embedded malicious content. Furthermore, it triggers a critical heuristic for CVE-2009-3129, a known vulnerability in Excel related to FEATHEADER record overflow. This suggests the file is designed to exploit this vulnerability upon opening, likely leading to arbitrary code execution.

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 158,219 bytes but its declared streams total only 24,565 bytes — 133,654 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).