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

Static analysis result for SHA-256 a3446a5b9a23636c…

MALICIOUS

Office (OOXML) / .XLSX

2.83 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2026-02-04
MD5: e64bdffdf590ff465e553612fa59e557 SHA-1: f25484a0bde76581e4005feec7a18754132fd290 SHA-256: a3446a5b9a23636ce98cf0feaf468777fa5956098d2d072989883885027bb140
100 Risk Score

Malware Insights

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

The sample is an Office document containing an embedded OLE object, specifically identified as a Equation Editor object. High-severity 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 pattern is commonly associated with the delivery of malicious payloads via weaponized documents.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/a0IWTrPPM.XfrgS87 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
f72d9f888016cd28325c8e47fa682fdef1aebf11e075f432444a92f5b214c791		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/a0IWTrPPM.XfrgS87 2854400 bytes
ooxml_oleobject_00_ole10native_00.bin
cb5dd8646c5b1d58b575b98f7e72953d2a34998e2718b86a015f3634df273a94		 ole-package OOXML xl/embeddings/a0IWTrPPM.XfrgS87 Ole10Native stream: OlE10nAtIVE 2829478 bytes

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