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

Static analysis result for SHA-256 c88b08ee12c176e9…

MALICIOUS

Office (OOXML) / .XLSX

2.90 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-12-10
MD5: 1486abd16d92657ad2ca6ab95aec47be SHA-1: fa6e272484b8ce08398aeabe1c384051feec924a SHA-256: c88b08ee12c176e941f6761c91fdfaa4674b38ef830f5a94c1ddd9f8cdfed575
100 Risk Score

Malware Insights

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

The 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 is a common technique for delivering second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/zX.qlj5 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
a4cbb8bac78576646f7beb5178486259e5b9358f3de663c89fe70d00f0480ce9		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/zX.qlj5 2957824 bytes
ooxml_oleobject_00_ole10native_00.bin
2b079606db0461d091aa15bcfda3eb4ce68c232cc5baded07fa59b8b3743f1ba		 ole-package OOXML xl/embeddings/zX.qlj5 Ole10Native stream: OLe10nATIvE 2931748 bytes

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