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

Static analysis result for SHA-256 f045903cf422b885…

MALICIOUS

Office (OOXML) / .XLSX

665.1 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-22
MD5: ef3cdc45f4d0fe60b3f7861ae78924f8 SHA-1: 8b90118de5c666a8c8925b28d0edebe8001b3f06 SHA-256: f045903cf422b88584f7dc13c9cadc6a10bdbbbc858e463d4232e0f23cdfb848
100 Risk Score

Malware Insights

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

The sample is an OOXML 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, suggesting it is designed to exploit a vulnerability. This points to a malicious document likely intended to deliver a second-stage payload upon opening.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/C3.J1 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
aaf6e55f78e98d97d3ac07dc775cf95d8b7db853131ecc3d9d376110131ff28c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/C3.J1 994304 bytes
ooxml_oleobject_00_ole10native_00.bin
5a62cc1ace8d14af5f52e4c6b743db07abf8484beff76f20ea331bc13b599204		 ole-package OOXML xl/embeddings/C3.J1 Ole10Native stream: ole10native 983959 bytes

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