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

Static analysis result for SHA-256 a88df2b5859ce488…

MALICIOUS

Office (OLE) / .XLS

76.8 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: f1210cf1c123be86c1839a2be75142e5 SHA-1: 40c2243042d56ee0037d609af10d8c76edc6cc12 SHA-256: a88df2b5859ce48862f47825f5cfdf08957fef79a75b986c1d3921a949dbcad2
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1204.002 Malicious File: Malicious Attachment T1059 Command and Scripting Interpreter T1059.003 Command and Scripting Interpreter: Windows Command Shell

The critical CVE-2009-3129 heuristic indicates a specific Excel FEATHEADER record overflow vulnerability is being exploited. This is often used to achieve arbitrary code execution. The suspicious cmd.exe invocation further suggests the execution of commands, likely to download and run a secondary payload. The embedded URLs, while not definitively malicious, point to potential external resources. The large slack space in the OLE document is also a common characteristic of exploit-laden files.

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 78,654 bytes but its declared streams total only 24,565 bytes — 54,089 bytes (69%) 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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