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

Static analysis result for SHA-256 07aea5803c83b618…

MALICIOUS

Office (OLE) / .XLS

76.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 87dcfd198bc571d3b9481339e7673814 SHA-1: 5590a9a0d0e21621440c570be1fa269e813a3ded SHA-256: 07aea5803c83b618bb1ad366239d179fd4bad7612f21a11957a0725b3dfadee5
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is a Microsoft Excel document that triggers a critical heuristic for CVE-2009-3129, indicating exploitation of a record overflow vulnerability. This vulnerability allows for arbitrary code execution on the victim's machine. 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=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 77,784 bytes but its declared streams total only 24,565 bytes — 53,219 bytes (68%) 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).