Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 66af1205b688b897…

MALICIOUS

Office (OOXML) / .XLSX

2.86 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2026-06-26
MD5: 91195d7416084297ecfe621a6e2c533f SHA-1: 2331b0b0dee648eda2c9ad79e7b88485f6b0cb89 SHA-256: 66af1205b688b89716ec84f17fb1df31c1cd8032527c27d21032c529f0adf15b
100 Risk Score

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/G5sin.BImD contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin ooxml-ole-object OOXML embedded OLE part: xl/embeddings/G5sin.BImD 2943488 bytes
SHA-256: 5a199b1ec13ce8232b2292fe2271c91b7d187e407b00810555579aec66132192
ooxml_oleobject_00_ole10native_00.bin ole-package OOXML xl/embeddings/G5sin.BImD Ole10Native stream: oLe10nAtIVE 2918374 bytes
SHA-256: 1f741461ecbfe2d84ee7c92740851f034e23b1dfa0d6dd90bca2430a6ff50af8

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