Office (OOXML) / .XLSX malware analysis — malicious · dfa326f34e1cee79

MALICIOUS

Office (OOXML) / .XLSX

632.0 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2024-08-01

MD5: fedda7e243aef236425384a981433e98 SHA-1: 95b33d7f3636a4dcd1ffab18473ab1ee133130fa SHA-256: dfa326f34e1cee79084e2b095c75b37ba6005a78fd63f9e96d3f6baa340aa4de

100 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.001 Malicious Link

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 being used to exploit a vulnerability. The anomaly in the declared inner size versus the stream size further supports this. The primary attack vector is likely the exploitation of a known Equation Editor vulnerability (e.g., CVE-2017-11882) to execute a secondary payload.

Heuristics 3

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/mGv.OPrg 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` `9e69efcbdc629d76c131c47389371f39cda0a3a4e56027947349d9aed1f164df`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/mGv.OPrg	921600 bytes
`ooxml_oleobject_00_ole10native_00.bin` `7916d9aedd72f81aea8fbcc265fd41733fa051ecc48ca36427bd6f582d58014c`	ole-package	OOXML xl/embeddings/mGv.OPrg Ole10Native stream: OLE10nATivE	911712 bytes

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