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

Static analysis result for SHA-256 a3d250f4f76972a5…

MALICIOUS

Office (OOXML) / .XLSX

650.4 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-04
MD5: 44f69868d76ec5a621ccd2b2d8f7a783 SHA-1: 343579902fd81700cbc3ec692fcad5b4fdd3c579 SHA-256: a3d250f4f76972a563abd50d988db62c14995ca8e2d390c32e92e7829d603f2a
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

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 difference, strongly suggesting exploitation of a known vulnerability within the Equation Editor component. This is a common delivery mechanism for malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/WbCrkxMv.jTcHR 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
39e67e33c815cee1ce8e428087143c935a769a6a7949f19f5e891dafc7f4d8ad		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/WbCrkxMv.jTcHR 964096 bytes
ooxml_oleobject_00_ole10native_00.bin
eabbb7040752c4615266b518bc9f01d624e2af62f98fb8043fc19da23e30b402		 ole-package OOXML xl/embeddings/WbCrkxMv.jTcHR Ole10Native stream: olE10naTIVe 953909 bytes

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