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

Static analysis result for SHA-256 1acab5ece6d9068a…

MALICIOUS

Office (OOXML) / .XLSX

2.85 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2026-02-17
MD5: d84c2f7114062a0ad39c29d282321d86 SHA-1: 4d9500022f22447d5b43c53c362fa92df15bfb42 SHA-256: 1acab5ece6d9068a9e1d5dd982480d781d745d9dff9f8a9008f4b546dbdb990d
100 Risk Score

Malware Insights

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

The sample is an Excel 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 size and entropy, strongly suggesting exploitation of a known vulnerability within Equation Editor. This is a common delivery mechanism for malicious payloads.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/MTc6f.BXAFFw 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
de1bd700e85a6b4f69a82b50177622cd52a6dc0ec1ac90924cc4a5bf7a4110a9		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/MTc6f.BXAFFw 2933760 bytes
ooxml_oleobject_00_ole10native_00.bin
247eb0302b0da069ca7645d04bb69c0ac07056127d9ab507ee712585695deaf3		 ole-package OOXML xl/embeddings/MTc6f.BXAFFw Ole10Native stream: Ole10nAtiVE 2908390 bytes

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