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

Static analysis result for SHA-256 a3773c187cb9358c…

MALICIOUS

Office (OOXML) / .XLSX

8.7 KB Created: 2025-04-13 05:16:34 UTC Authoring application: Microsoft Excel 15.0300
MD5: 0a48cf52311936211d6aa218a16f107b SHA-1: 4e4aeb9057432cda10d31c215f47276126c6234b SHA-256: a3773c187cb9358c2cfc2eb616564e98a07dcccdc11d5fa2276784bc95a8b5ff
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate an anomaly in the Equation Editor's native stream, strongly suggesting exploitation of CVE-2018-0798. This vulnerability allows for arbitrary code execution when the embedded object is activated.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • 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
bdf2086ba283ec42e899bf66d9576038552f4d336ad711c79426226781625901		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4096 bytes
ooxml_oleobject_00_ole10native_00.bin
471952b4c9835c91b279fc1eaeb2dd6b2316284ba7f3cc1cc7b25ff0c3c65595		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 1746 bytes

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