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

Static analysis result for SHA-256 b98edfd28820ec10…

MALICIOUS

Office (OOXML) / .XLSX

2.82 MB Created: 2025-09-10 01:57:00 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2025-10-28
MD5: 0ab74b8044682208325db46d23f7367f SHA-1: 2ea301a253a7537b8723f678d2f1ac738ba6aef3 SHA-256: b98edfd28820ec109133049fba0bdeaa887a9f447831e0218f73f3014fe38bf8
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link

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 being used to deliver a secondary exploit or payload. The file's structure and the nature of the embedded object strongly indicate an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882) for malicious purposes.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/f5N6eVRI.vcfZK 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
09ccf0c19abaf3142a436dbd177badffc38290e643429ba4850630c4d151fb27		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/f5N6eVRI.vcfZK 2908160 bytes
ooxml_oleobject_00_ole10native_00.bin
0d4e979dca3353740593eb0cc2e6e502d770062332b5ec9900930cd14b707a26		 ole-package OOXML xl/embeddings/f5N6eVRI.vcfZK Ole10Native stream: OlE10nativE 2882682 bytes

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