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

Static analysis result for SHA-256 d19745deb0027f8e…

MALICIOUS

Office (OLE) / .XLS

102.1 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 573a54560bfe4715f6f2465cc80a46c1 SHA-1: e1bf9c8abbd7894d702aa6d3c2efa0b20f3b8f7a SHA-256: d19745deb0027f8e8e8da878133459bcc91a7a44756217a5a38b1dbcaefa22a6
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.003 Windows Command Shell

The sample is a malicious Microsoft Excel file that exploits CVE-2009-3129 via a FEATHEADER record overflow. High severity heuristics indicate suspicious cmd.exe invocation and PEB access, suggesting the exploit is used to execute arbitrary code. The presence of a NOP sled further supports code execution. The large slack space in the OLE structure is also anomalous. The primary IOC is the CVE identifier itself, as no specific URLs or hashes were extracted.

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 104,510 bytes but its declared streams total only 24,565 bytes — 79,945 bytes (76%) 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).
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.pdf-repair.com
    • http://www.pdf-repair.com)/Producer(Advanced
    • http://www.pdf-repair.com)/ModDate(D:20100406171120+08
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

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