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

Static analysis result for SHA-256 0f62d1d38f7f1dbe…

MALICIOUS

Office (OOXML) / .XLSX

2.79 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300
MD5: b98d885d039cb603c236430033bf44fd SHA-1: 86b114062037788bc908f24669d47cd231e99e07 SHA-256: 0f62d1d38f7f1dbe188bf17b3b142a8a121a1fa98a0851c1b8cb3ecb202931c8
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an Office Open XML 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, strongly suggesting it is used to exploit a vulnerability for client execution. The embedded object's path and the stream name are the primary indicators of compromise.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/YAd47zp.To1 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
b299398761a088dd683eea673fafe7635e1fa74ff1639ebf97b5c1e8ca4eb4f0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/YAd47zp.To1 2825728 bytes
ooxml_oleobject_00_ole10native_00.bin
da26bfb2c11276c676401f516b22dbad2ca4fc8efdb5fd478cec04183200f301		 ole-package OOXML xl/embeddings/YAd47zp.To1 Ole10Native stream: ole10naTIVe 2801133 bytes

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