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

Static analysis result for SHA-256 196d10b10d2cc4be…

MALICIOUS

Office (OLE) / .XLS

82.4 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 14f6bdcafb4b8404fda852feea3a86ed SHA-1: 44bf244790ba536726440366814b5b93405ecc57 SHA-256: 196d10b10d2cc4be399ade724a1811b1700a92180a92b031efa2eba31030d22e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The critical heuristic firing indicates exploitation of CVE-2009-3129, a known vulnerability in Microsoft Excel. This vulnerability allows for arbitrary code execution, likely leading to the download and execution of a secondary payload. The OLE slack anomaly and GetPC stub further support the malicious nature of the file.

Heuristics 3

  • 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.
  • x86 GetPC stub (CALL $+5; POP EDI) high SC_GETPC_CALL
    x86 GetPC stub (CALL $+5; POP EDI)
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 84,362 bytes but its declared streams total only 24,565 bytes — 59,797 bytes (71%) 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).