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

Static analysis result for SHA-256 a8fa3fa59063bb91…

MALICIOUS

Office (OOXML) / .XLSX

2.05 MB Created: 2025-06-12 01:12:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-06-25
MD5: 8dc1982c32a7a41cfb4fd743ac715cc1 SHA-1: 6ad1a53a2ce585ba497b640c43414548830dda1e SHA-256: a8fa3fa59063bb91e71de13eebdcd7755f63a72756819ca15418a1de1a429b01
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Phishing: Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is an Office Open XML (OOXML) file 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 header, suggesting it's being used to exploit a known vulnerability for client execution. The embedded object's path and 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/qZN.H17H5 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
3f0f07e7af4bf45a313e1555740d3880056c6144191728e759dc0e129470e68c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/qZN.H17H5 2898944 bytes
ooxml_oleobject_00_ole10native_00.bin
fcbc059078b4ad3505bf25abf3cb498d615b5de4e7c5cad1ddc7723dc5ab4737		 ole-package OOXML xl/embeddings/qZN.H17H5 Ole10Native stream: oLe10nATiVe 2873540 bytes

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