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

Static analysis result for SHA-256 c9cb689039fbc49b…

MALICIOUS

Office (OOXML) / .XLSX

2.81 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-12-05
MD5: 2bbdd32bb0d3213b32b6514db70c47e9 SHA-1: 7bdab88b6e4e650efb234afc0f45a408984f401f SHA-256: c9cb689039fbc49bd0182c82357b1d3763606e3c544f801722316f23f443e963
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The sample is an Excel file 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 designed to exploit a vulnerability. This is a common delivery mechanism for malware that relies on user interaction to execute.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/HcX.jRjp2 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
fa4faad11786656e4d51590a18382353986f20d8d3ecc51fa259b741cfd330ca		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/HcX.jRjp2 2859520 bytes
ooxml_oleobject_00_ole10native_00.bin
1bfb81a63c767d959c5152604070120435cdaea3db25c9ac17a4ac2ddd502e40		 ole-package OOXML xl/embeddings/HcX.jRjp2 Ole10Native stream: OLe10NaTIvE 2834768 bytes

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