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

Static analysis result for SHA-256 fd41f268a1dbe0e0…

MALICIOUS

Office (OOXML) / .XLSX

2.12 MB Created: 2025-06-12 01:12:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-12-16
MD5: 55c30ea60b114d29ee2935d9428f35c5 SHA-1: f41a16f1e5ac1923103496d8feca082b94ab7c3f SHA-256: fd41f268a1dbe0e0e5e6385f1bde034d04b3dc75f1f195acd0d630b7ee395230
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model and Distributed Component Object Model

The XLSX file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it is being used to exploit a vulnerability. This points to an attack pattern focused on exploiting the Equation Editor to execute a malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/3aG9iRWF.TcWjV 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
f7c79913c6d895ee33538834c6c78b623886a3f2a60151ab6ed41dc27530b9a1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/3aG9iRWF.TcWjV 2993664 bytes
ooxml_oleobject_00_ole10native_00.bin
033b186bf68bfd5aee5de22a62f88fd4ecf6133bcd8e9ded075d707b1e23d64a		 ole-package OOXML xl/embeddings/3aG9iRWF.TcWjV Ole10Native stream: olE10natIVE 2967985 bytes

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