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

Static analysis result for SHA-256 71aba23b18fd91b1…

MALICIOUS

Office (OOXML) / .XLSX

2.89 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2026-02-05
MD5: 3ff91a95a47288b1b002fc87cfc6ea99 SHA-1: 300438d01a6e9e105ccd1c1d1b91b3575d654760 SHA-256: 71aba23b18fd91b1fa4b9844b86d6818343a0799e7f99b75ea64de48c21688f8
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample contains a high-severity heuristic indicating an embedded Equation Editor OLE object. This object, specifically the 'Ole10Native' stream within it, exhibits anomalous characteristics suggesting it carries a malicious payload. The presence of an embedded OLE object, particularly one associated with Equation Editor, strongly points towards exploitation for client execution.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/goJq3H.nlcFTN 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
2aa09461ad09095e53758600c0153333d0030ec6cf875af7ed2af21dc817dd9c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/goJq3H.nlcFTN 2985984 bytes
ooxml_oleobject_00_ole10native_00.bin
3941389c390784112ffcc7d790d432cf9a23e564c1629dda7a011e2f47a44d9b		 ole-package OOXML xl/embeddings/goJq3H.nlcFTN Ole10Native stream: olE10NaTIvE 2959887 bytes

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