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

Static analysis result for SHA-256 8f9c3c605f01435a…

MALICIOUS

Office (OOXML) / .XLSX

723.8 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-28
MD5: cd7be02e43a9df831bfa8d9bea3a5cb3 SHA-1: 230156928b9e51ccc2f2b9ec40b30cab7b5cd920 SHA-256: 8f9c3c605f01435a65bbfbc042d64e96bc3f116105327a9ff25ded111ab9f317
100 Risk Score

Malware Insights

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

The XLSX file contains 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 size discrepancy, 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/TOy1.btmgV 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
7e71cbec2edc4b91b1b16231c56a705495dd1d79b9b5e5c89c06e909bdbd74e3		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/TOy1.btmgV 991744 bytes
ooxml_oleobject_00_ole10native_00.bin
775aa1fcb43274c197fcae453a80175e017061f40096c9a7902832a4a46416e5		 ole-package OOXML xl/embeddings/TOy1.btmgV Ole10Native stream: OLE10naTIvE 981227 bytes

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