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

Static analysis result for SHA-256 c661311105d152d5…

MALICIOUS

Office (OOXML) / .XLSX

2.03 MB Created: 2025-06-12 01:12:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-06-25
MD5: 25428fa291a093f37c920b8c28a7535d SHA-1: b3bc7136a5fd4394376d3c8687b96e73c86b273c SHA-256: c661311105d152d574eddf226c3943180e839b8158ce3605a8ff27b0f9711cb3
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File

The XLSX file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. This object carries a payload-like Ole10Native stream with an anomalous header, indicating it's likely an exploit targeting the Equation Editor vulnerability. The presence of this exploit suggests the file is designed to download and execute a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/NFKV.oSpTGqc 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
f717596518a64663af50c92e5a56429d22fb065ca6cb84f925b1c994f5acc1dd		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/NFKV.oSpTGqc 2882048 bytes
ooxml_oleobject_00_ole10native_00.bin
705d69c858bb4177d4889e7538fcc8342671cc737603f0fb5ff895545271f91e		 ole-package OOXML xl/embeddings/NFKV.oSpTGqc Ole10Native stream: oLE10natIvE 2857041 bytes

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