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

Static analysis result for SHA-256 e3087643b2999d4e…

MALICIOUS

Office (OLE) / .XLS

124.6 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 32dcce3e1d86eb937fddc001e4fd9a92 SHA-1: ba9eb0c9da4a9447e815cc89b8dbe2378a3c787a SHA-256: e3087643b2999d4ee97e11111d05ee97b07636758ad5db9b62dc83d73704586d
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

The critical heuristic firing indicates exploitation of CVE-2009-3129, a known vulnerability in Microsoft Excel. This vulnerability is often leveraged to execute arbitrary code, typically leading to the download and execution of a secondary payload. The large slack space anomaly further suggests the presence of embedded malicious content.

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 127,574 bytes but its declared streams total only 24,565 bytes — 103,009 bytes (81%) 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).