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

Static analysis result for SHA-256 6d701ce837905a00…

MALICIOUS

Office (OLE) / .XLS

181.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 0cb37ec1068d09c0ec9bd0e88a733c5e SHA-1: 3f0ae3afaa47ca0029355ed1c8d6f76925ff482b SHA-256: 6d701ce837905a00511fa0abe9f96386b461129644ecc995b5782a63a04183aa
260 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is a malicious Microsoft Excel document that exploits CVE-2009-3129, a FEATHEADER record overflow vulnerability. This vulnerability allows for arbitrary code execution, likely to download and run a second-stage payload. Heuristics indicate a suspicious invocation of cmd.exe, suggesting command execution capabilities, and the presence of an appended executable payload.

Heuristics 6

  • 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.
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 185,896 bytes but its declared streams total only 24,565 bytes — 161,331 bytes (87%) 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).
  • OLE file has appended executable-looking payload bytes high OLE_APPENDED_PAYLOAD
    OLE compound file contains a large high-entropy region beyond the declared major streams and that region includes shellcode, PE, or loader API markers. This is a payload-carrier signal, not a specific CVE attribution by itself.