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

Static analysis result for SHA-256 f1e440fbb11c1896…

MALICIOUS

Office (OOXML) / .XLSX

2.05 MB Created: 2025-06-12 01:12:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-06-16
MD5: 88689bf219765924fe3daa198404cb5f SHA-1: cbfb9df621d6e3dc9d472ffd0fd4bead4b8460c4 SHA-256: f1e440fbb11c1896f576a2a268ae52a67f93e0ad98f6c7d3fb15018af9f5e68b
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link T1027 Obfuscated Files or Information

The sample is an Excel file containing an embedded OLE object, specifically identified as a Equation Editor object. This object exhibits an anomaly where the Ole10Native stream is unusually large and has characteristics of a payload, strongly suggesting exploitation of a known Equation Editor vulnerability. The embedded object itself is the primary indicator of compromise.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/DT9DK3trB.NPc4l 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
464e5d6cb9636252445c70e79e463df559232f42183223afbfa933c4ca694de3		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/DT9DK3trB.NPc4l 2892288 bytes
ooxml_oleobject_00_ole10native_00.bin
716c0e5da07b0007b56b2bcaf352585540c008a7f077118e36f9f5a657063295		 ole-package OOXML xl/embeddings/DT9DK3trB.NPc4l Ole10Native stream: oLE10naTIVe 2867152 bytes

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