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

Static analysis result for SHA-256 ad6c520c6639f088…

MALICIOUS

Office (OLE) / .XLS

123.2 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 42d8a6b993a0c5dd1eeef5f619ba3baa SHA-1: d78de871d891e7b8b18a10a547bd5ec7a93a6df2 SHA-256: ad6c520c6639f0888f30d34715e7a6f97f70d4468cd23bb39df72e39a591cc10
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

The sample is an Excel file exhibiting a large slack space anomaly and a critical heuristic firing for CVE-2009-3129, indicating an exploit targeting a known Excel vulnerability. The embedded URLs, while mostly benign, include references to 'pdf-repair.com' which may be a lure. The exploit likely leads to the download and execution of a second-stage payload, though no scripts were directly extracted to confirm this.

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=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 126,166 bytes but its declared streams total only 24,565 bytes — 101,601 bytes (81%) 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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