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

Static analysis result for SHA-256 85f67179a4991093…

MALICIOUS

Office (OLE) / .XLS

100.3 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 39ed4f79750a6227e9c14d25a8dbb1aa SHA-1: bdcd8ee84a8fc2a73d98da0b15951c7c38800e8e SHA-256: 85f67179a4991093df566eb7c36716a578165a0664fa9e753e59ae6d0fc555b0
180 Risk Score

Malware Insights

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

The file is an Excel spreadsheet that contains a critical heuristic indicating exploitation of CVE-2009-3129, a known vulnerability in Excel. This vulnerability allows for arbitrary code execution. Additionally, suspicious cmd.exe invocation and PEB access heuristics suggest post-exploitation activity. The large slack space in the OLE structure is also indicative of a packed or obfuscated 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 102,718 bytes but its declared streams total only 24,565 bytes — 78,153 bytes (76%) 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/