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

Static analysis result for SHA-256 a9a956a1420a296c…

MALICIOUS

Office (OOXML) / .XLSX

2.80 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-10-29
MD5: 34fedcab0529de15602c188d25d156fc SHA-1: ee0c01fae6817c7cae901595224052fa2b216160 SHA-256: a9a956a1420a296c29d8cf9053ce1264026bd4a6477c6a3b46f891906b4a0c35
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size and entropy, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to deliver a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/psVjN.YNDjG 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
9525326d8de4d3fdf049f3a394d255f45299e6cc1bfeac47b618791c2dd83ad0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/psVjN.YNDjG 2870272 bytes
ooxml_oleobject_00_ole10native_00.bin
75fade5dbddc630d2e01ebfedd94605b63105ae40f0983b2e554c04f61a6416a		 ole-package OOXML xl/embeddings/psVjN.YNDjG Ole10Native stream: OlE10NATIVe 2845549 bytes

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