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

Static analysis result for SHA-256 bad943cb91191c65…

MALICIOUS

Office (OOXML) / .XLSX

2.95 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-10-28
MD5: 81100af35165638e57296beb499b179e SHA-1: 32ce1da3631612e414f135e7d78e67b3a83216ef SHA-256: bad943cb91191c65c0032dfc79e689802c2cbf9a968e4bff79da72b7d5aa6878
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an OOXML document 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 header, suggesting it's being used to exploit a vulnerability. This is a common delivery mechanism for malware that leverages known exploits in embedded objects.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/9M.Hh 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
27fb87a1670931f3bbc64fb75f98f43ea37d5005438c63966a5d8b9eda72d987		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/9M.Hh 3096576 bytes
ooxml_oleobject_00_ole10native_00.bin
4e9f7bb2fa3bfa299e847c5f53cce1dd7be7d563e02a1e9479be111ef0727a05		 ole-package OOXML xl/embeddings/9M.Hh Ole10Native stream: ole10natIVe 3069792 bytes

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