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

Static analysis result for SHA-256 db9a170ef7a06418…

MALICIOUS

Office (OOXML) / .XLSX

2.17 MB Created: 2025-08-18 05:08:49 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-08-19
MD5: f42f9db165a57fec73784df0e21eee1d SHA-1: 00a31b37b92769cb1a02026b2a774af0a6ea9768 SHA-256: db9a170ef7a064184dbf89b1bf8332b82d769b237aea824b7c030b7305038d74
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The file is an Excel document 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 header and a significantly larger declared inner size than the stream size. This strongly suggests the exploitation of a known vulnerability within the Equation Editor to embed and deliver a malicious payload. No document body text or scripts were extracted, but the presence of the anomalous OLE object is sufficient evidence for this assessment.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/9cMA.Fov 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
aa761a4b6c6dc583520da39d3a783723ae920c0b0ce665ebf88335e8b55675fe		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/9cMA.Fov 3036672 bytes
ooxml_oleobject_00_ole10native_00.bin
0143f00b83c65f48b8c7343e4e6715814a7ae5479dd00c5e864721308963d59c		 ole-package OOXML xl/embeddings/9cMA.Fov Ole10Native stream: OLe10NaTive 3010557 bytes

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