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

Static analysis result for SHA-256 76e3a80440191f0c…

MALICIOUS

Office (OLE) / .XLS

112.1 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: ad1f911639cebf1fde8dda8df2f656c8 SHA-1: 1dccc123aa8694e3d087563fbe4c369324f041d2 SHA-256: 76e3a80440191f0cec2b7f13461714329d8dc6a60fbf3b1544b8c90b00e0bb6e
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is an Excel spreadsheet exhibiting characteristics of a malicious document, including a large slack space and an appended executable payload. It triggers a critical heuristic for CVE-2009-3129, a known Excel vulnerability, and a high-severity heuristic for suspicious cmd.exe invocation. These indicators suggest the file is designed to exploit this vulnerability to achieve code execution, likely for downloading and running a secondary payload. The presence of URLs related to 'pdf-repair.com' may indicate a lure, though their reputation is unknown.

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=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.
  • 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 114,750 bytes but its declared streams total only 24,565 bytes — 90,185 bytes (79%) 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.
  • 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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