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

Static analysis result for SHA-256 c15c61f1f1954ccd…

MALICIOUS

Office (OLE) / .XLS

335.6 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 01ff68e6f7045df2038cf2f2988bcefb SHA-1: a8d1a82e101b5466080be75aa0f74b7068f35360 SHA-256: c15c61f1f1954ccdca38f68b770a84eef461e6ce3a97b9e29c693ce1b43728e1
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1059 Command and Scripting Interpreter T1059.003 Command and Scripting Interpreter: Windows Command Shell

The sample is an Excel 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 suggest post-exploitation activity. The large slack space in the OLE document is also anomalous. While no scripts were extracted, the presence of embedded URLs and the exploit itself strongly suggest a malicious intent, likely to download and execute a secondary payload.

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 343,614 bytes but its declared streams total only 24,565 bytes — 319,049 bytes (93%) 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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