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

Static analysis result for SHA-256 fdf1924943ec339c…

MALICIOUS

Office (OOXML) / .XLSX

2.78 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-09-25
MD5: a467866fa1f99a4ee4f39a9a760fd497 SHA-1: 1ed73dbdfe0a17ea54581c2372174dfea5318e4e SHA-256: fdf1924943ec339c2e867d41675b1fe9d79546a61813340eb8c5571809917122
100 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded OLE object, specifically identified as a malicious Equation Editor object. This object carries a payload-sized Ole10Native stream, indicating it's designed to exploit vulnerabilities within the Equation Editor component to execute malicious code. The presence of this exploit suggests a delivery mechanism aimed at users opening the document.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/R2Fl.Jtj 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
3c17ff35459aea89a892168e711344339c213e22149aef1445e73446971e3078		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/R2Fl.Jtj 2785280 bytes
ooxml_oleobject_00_ole10native_00.bin
1be1f5a27bd03c88dd90f0ca1f1fb64d4953be9fc418c39232b2baa1186a7c91		 ole-package OOXML xl/embeddings/R2Fl.Jtj Ole10Native stream: OLe10natIvE 2760975 bytes

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