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

Static analysis result for SHA-256 98386015855a4ed5…

MALICIOUS

Office (OOXML) / .XLSX

1.97 MB Created: 2025-06-12 01:12:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-10-16
MD5: 3069a50ba3dea385f6f3258894b6d4e8 SHA-1: 7cd1ed6ee4e2d7e64c22c9e93592e7e8b9660789 SHA-256: 98386015855a4ed56c58a7701b69a1d4f7b7fac0b0f78bc00de5f23ac5a378a9
100 Risk Score

Malware Insights

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

The sample is an Office Open XML spreadsheet containing 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 size, strongly suggesting it's being used to exploit a vulnerability. This is a common delivery mechanism for malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/MdmBTH.duoIu 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
53a8c1135afdc7ffff9da174581984eab5e0ac2ba76ff2639266f2dd34a267b5		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/MdmBTH.duoIu 2780672 bytes
ooxml_oleobject_00_ole10native_00.bin
6f1899c8d5756430808431c6c0edbf4542243508eff4fa3ac41756af83ce0895		 ole-package OOXML xl/embeddings/MdmBTH.duoIu Ole10Native stream: OLe10NatIve 2756242 bytes

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