Office (OOXML) / .XLSX malware analysis — malicious · 4d1fbeca1370d7cd

MALICIOUS

Office (OOXML) / .XLSX

1.60 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 15.0300

MD5: 72774cf9537a90f3e44c4e7aaa6b5036 SHA-1: b482bd1f388e0a21b53bc479a508fd4118f8f2cd SHA-256: 4d1fbeca1370d7cdcf552ea717addc311fadb1293d35cd5ee1d04006de30a620

142 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. Heuristics indicate this object is anomalous and likely carries a payload, exploiting CVE-2018-0798. The embedded Ole10Native stream is suspicious due to its size and entropy, suggesting it contains malicious code designed to be executed.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY

Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
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
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `f1b717f125ec9609cf1a50c250b2994183364775be98c25142b2e08dcdfd07e8`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	1620992 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `3f4f7b4bd16cd0802b6987a0f2693b2c8ee6a5e80d1a045c7369cfae1613cc34`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: olE10NaTIVe	1606140 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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