Office (OOXML) / .XLSX malware analysis — malicious · 87937d8e251601ab

MALICIOUS

Office (OOXML) / .XLSX

1.43 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-05-18

MD5: 4e6628e5f18ab15aac6fd96ef95b656d SHA-1: 71414122a1f431f62087841084e200955e2b20b8 SHA-256: 87937d8e251601ab750fc53c6fed7e34f1f4400cad227e5083aae26ac09daf4a

102 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The sample is an OOXML file containing an embedded OLE object identified as an Equation Editor. This object's Ole10Native stream exhibits high entropy and a size anomaly, strongly indicating it carries a malicious payload. The presence of this object suggests exploitation for client execution, likely to deliver a secondary stage.

Heuristics 4

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/ajB2yAG.Rbgi2 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
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` `7e9bba03e9894f4338479e2471f97af42591c0c2046b345d9d6cf37f886d9276`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/ajB2yAG.Rbgi2	1744384 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.98, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `f1d3990149603cd6bcba4fddfa486f48c1fad0d75bbb8d5adcf4bffb96475442`	ole-package	OOXML xl/embeddings/ajB2yAG.Rbgi2 Ole10Native stream: oLe10nATIvE	1728009 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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