Office (OOXML) / .XLSX malware analysis — malicious · 59df7ebde2f9db5a

MALICIOUS

Office (OOXML) / .XLSX

1.02 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-04-27

MD5: 5b47098a17ecd534de15df03b12beacb SHA-1: a4dbe70e2448e497fa783a00a3f5eebfa4dac85d SHA-256: 59df7ebde2f9db5aae9ac2d7db37e0d6e278ddb1cfa7512edd61f233df0ff33a

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an OOXML document containing an embedded OLE object, specifically an Equation Editor object. High-severity heuristics indicate exploitation of CVE-2018-0798 due to anomalies in the Equation Editor's native stream. This suggests the object is designed to carry and execute a malicious payload, likely a second-stage downloader or exploit.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/Et0.fKkbP 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` `861b879ba52e5071c06a7eb95e39dc23bdf9b03944a436008369a6d0e5f74940`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/Et0.fKkbP	1298432 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.78, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `edd37f01de8961e4b9f0917e52527559a6f51c21e0806a6249bc22f28c4d5250`	ole-package	OOXML xl/embeddings/Et0.fKkbP Ole10Native stream: OlE10nATiVe	1285762 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.78, consistent with packed or encrypted content.

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