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

Static analysis result for SHA-256 077f6bfda56e54cd…

MALICIOUS

Office (OLE) / .XLS

186.6 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 126caf86014d1b375bf7abebdeb5f75c SHA-1: 035e165b0e02a7fb01faddab063e6da9fb1ec065 SHA-256: 077f6bfda56e54cd9a902c2edb9660800419fe27680b55811e51e4651cc4ea1d
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is identified as malicious due to the critical CVE-2009-3129 heuristic, indicating an Excel FEATHEADER record overflow vulnerability. This exploit likely allows for arbitrary code execution, potentially downloading and executing a second-stage payload. Suspicious cmd.exe invocation and appended executable bytes further support this assessment. The presence of unknown URLs suggests potential C2 communication or payload hosting.

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.
  • 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 191,038 bytes but its declared streams total only 24,565 bytes — 166,473 bytes (87%) 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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