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

Static analysis result for SHA-256 fc4937535bf55bd4…

MALICIOUS

Office (OLE) / .XLS

72.1 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2026-05-10
MD5: 3e183f97cf36a6bab227e9c1d277f1bc SHA-1: 3a160a6be3ec18b05056c3664764e9d69b0eb9f3 SHA-256: fc4937535bf55bd49cd7941539219dbe4130d26df5d21e861ca99b12f4fe5153
102 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment

The file is an OLE document with a large amount of slack space, suggesting potential obfuscation or embedded content. No VBA macros could be extracted due to an unsupported format. The document body is minimal, but embedded URLs point to 'pdf-repair.com', indicating a potential lure to a website that may host malicious content or engage in social engineering for repair services. The confidence is lowered due to the inability to analyze VBA macros.

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.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 73,790 bytes but its declared streams total only 24,565 bytes — 49,225 bytes (67%) 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 In document text (OLE body)
    • http://www.pdf-repair.com)/Producer(AdvancedIn document text (OLE body)
    • http://www.pdf-repair.com)/ModDate(D:20100406171120+08In document text (OLE body)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OLE body)
    • http://ns.adobe.com/pdf/1.3/In document text (OLE body)
    • http://ns.adobe.com/xap/1.0/In document text (OLE body)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OLE body)
    • http://purl.org/dc/elements/1.1/In document text (OLE body)

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