Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b6afc4fa09db5e9e…

MALICIOUS

Office (OLE)

104.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 3eb45009e27518dc441992782b47e476 SHA-1: 51139b6023e5341551c994cb4f70d9a530c7dac7 SHA-256: b6afc4fa09db5e9e1ecc61ca8d4cb1b6a338801e4917745337d3aaec87efb8e7
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.003 Windows Command Shell

The sample is an Excel OLE document exhibiting a large slack space anomaly and triggering a critical heuristic for CVE-2009-3129, a known Excel FEATHEADER record overflow vulnerability. This indicates the file is designed to exploit this flaw. Additionally, a suspicious invocation of cmd.exe with an execution flag was detected, suggesting the exploit is used to run commands. The embedded URLs, while mostly benign, include references to 'pdf-repair.com', which may be a lure. The overall pattern suggests a downloader or initial access exploit.

Heuristics 5

  • 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.
  • 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 107,046 bytes but its declared streams total only 24,565 bytes — 82,481 bytes (77%) 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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