Office (OOXML) / .XLSX malware analysis — malicious · fb079022ee100b50

MALICIOUS

Office (OOXML) / .XLSX

2.39 MB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-15

MD5: 2623fca6cc2f795a71ac9aaf3257387f SHA-1: d447141f6288ec5b8b8ae7385627b42eb18f2f43 SHA-256: fb079022ee100b50b3048761db972e012f1e3dc2f140f6d5c63a8922ffef7d6b

142 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an Excel document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate anomalies within the Equation Editor's native stream, strongly suggesting it's being used to exploit CVE-2018-0798. This exploit likely facilitates the execution of a second-stage payload, though the specific payload and its delivery mechanism are not detailed in the static analysis.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/kGiEIl5sN.29S0Z 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` `cb2ddedb4e749549e7298985677e3b3b99ba837a8849f9fab9127a58722697e2`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/kGiEIl5sN.29S0Z	2764288 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.97, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `4fa9d563a977bacc449ab0f6d92c3353ba6f3865e0d1ae60a612c47a19154061`	ole-package	OOXML xl/embeddings/kGiEIl5sN.29S0Z Ole10Native stream: ole10naTiVE	2739859 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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