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

Static analysis result for SHA-256 28ebfb5c077f1993…

MALICIOUS

Office (OOXML) / .XLSX

2.80 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2026-02-26
MD5: 71024a72e8029e23de71b7c1fc03be8f SHA-1: da1029931391da3b04f242c8005e1781b71a37f2 SHA-256: 28ebfb5c077f199343d52a02c097984f884a778da27aca59680cc8b2be3b362c
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The sample is an Excel 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 size and header, strongly suggesting exploitation of a vulnerability within the Equation Editor component. 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/gOiav.eZl4ReR 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
2d9946ebf6f9c3741ffd5d64f83170850cd54bbac63fcde02506cda0b3c94625		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/gOiav.eZl4ReR 2809344 bytes
ooxml_oleobject_00_ole10native_00.bin
284148877568f054f1feeddb6397b9cd5ca1fece850270abb81609586524bb66		 ole-package OOXML xl/embeddings/gOiav.eZl4ReR Ole10Native stream: Ole10NativE 2785109 bytes

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