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

Static analysis result for SHA-256 399f3e342b8fa8eb…

MALICIOUS

Office (OLE) / .XLS

158.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 4357a09fa6b309913a2ee290b5775e04 SHA-1: 9103ef115464fb3f8240752586bc45bf726f59b0 SHA-256: 399f3e342b8fa8eb2aa68aae08028d973f1bdda36c4df6d3499a945aa5c2f614
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.003 Windows Command Shell

The sample is an Excel XLS file that triggers a critical heuristic for CVE-2009-3129, indicating an exploit for a known Excel vulnerability. High severity heuristics for PEB access and suspicious cmd.exe invocation further suggest malicious code execution. The large slack space in the OLE document is also anomalous. While no specific malware family is identified, the exploit and command execution indicators point to a malicious payload delivery.

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 161,830 bytes but its declared streams total only 24,565 bytes — 137,265 bytes (85%) 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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