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

Static analysis result for SHA-256 eea18a63bd83a19d…

MALICIOUS

Office (OOXML) / .XLSX

2.15 MB Created: 2025-08-18 05:08:49 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-08-21
MD5: 3e2660ad71fe1b622096b1458c8bfc91 SHA-1: 190918330003b955ece1c60a8ea662f82cf27236 SHA-256: eea18a63bd83a19dc4cd25ff51bc1188aab33b96e5e24e93763c8306b66abcfc
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1137.001 DLL Search Order Hijacking

The sample is an Excel file containing an embedded Equation Editor OLE object. Heuristics indicate that this object carries a payload-like Ole10Native stream with an anomalous size and entropy, suggesting it's not standard Equation Editor content. The document body contains repetitive, nonsensical text, likely a lure to obscure the malicious embedded object.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/7A9lU.jkaq 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
fafac9d9e5f32eed676c22f278074829bc1f88e5baafdebf03b17d4f2dcc5eca		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/7A9lU.jkaq 3057664 bytes
ooxml_oleobject_00_ole10native_00.bin
18fcccc35e419cb280e7e3fdedc146008ed8cdada6be56e018615ec2d13f7852		 ole-package OOXML xl/embeddings/7A9lU.jkaq Ole10Native stream: olE10NATivE 3031045 bytes

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