Office (OOXML) / .XLSX malware analysis — malicious · 0354bd9fec1e1a41

MALICIOUS

Office (OOXML) / .XLSX

4.19 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000

MD5: 9d1a5234ffd4001ee057acdf4106c85e SHA-1: 70c294698d94f856bd60c188075470402d26c1e6 SHA-256: 0354bd9fec1e1a41e3b0166e17a4b30b002c94cfe00239b79c728ddf3a9a8b77

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing an embedded OLE object, specifically an Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and likely carries a malicious payload, exploiting CVE-2018-0798. This suggests the file is designed to execute arbitrary code upon opening.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/22L.ki6jO2 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` `ff8eabc1888014a5434e9bd8d52ef3a5023f5a17ee9e83f8f4af1d28295c8e3a`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/22L.ki6jO2	4656640 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.92, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `c26fdd6009e5f86b6efed6803ad92cb39e637d8aa3d7de7b67114d8400719169`	ole-package	OOXML xl/embeddings/22L.ki6jO2 Ole10Native stream: Ole10NatIVe	4617428 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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