Office (OOXML) / .XLSX malware analysis — malicious · 125bfc7a666a4fdd

MALICIOUS

Office (OOXML) / .XLSX

733.8 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-07-31

MD5: 8c50b11509ba38317ee8520420b56a9c SHA-1: 20698c6468f72b924c1dff2c162f5bc636054800 SHA-256: 125bfc7a666a4fddf58a9ce69bc5cb16f84d804c1d622fbff0958bae16b8c98a

100 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Office Open XML spreadsheet 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, strongly suggesting exploitation of a known vulnerability (e.g., CVE-2017-11882) to execute arbitrary code. The embedded OLE object itself is the primary indicator of compromise.

Heuristics 3

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/10ef.bPr 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.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `5a09a0be4f581ddaf694d211bd525ed14868ffca2f1e625be79a9a30b9286e0d`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/10ef.bPr	1031680 bytes
`ooxml_oleobject_00_ole10native_00.bin` `85d1de4b5827a956f08e7fb3c13b472470cefbf3c14cc261d1696f502886a402`	ole-package	OOXML xl/embeddings/10ef.bPr Ole10Native stream: OLe10naTIve	1021015 bytes

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