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

Static analysis result for SHA-256 abcf158ab733db7c…

MALICIOUS

Office (OLE) / .XLS

107.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: c799446dca2ba89f7bf9be7f4d22208d SHA-1: 4b98343dc91754f1cb8e5adcff23a34497a6379a SHA-256: abcf158ab733db7c9e86a11dd5968e00f4675e93ef2b445230cebebf911975b2
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 allows for arbitrary code execution when the malicious file is opened. The large slack space in the OLE document further suggests the presence of embedded malicious content. No document body or scripts were extracted, but the exploit itself is sufficient to classify this as malicious.

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 109,575 bytes but its declared streams total only 24,565 bytes — 85,010 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).