Office (OOXML) / .XLSX malware analysis — malicious · 75342e6fc49d7c23

MALICIOUS

Office (OOXML) / .XLSX

1.06 MB Created: 2022-09-22 07:50:17 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-09-27

MD5: 5c90aacb5ee79113a88477d6e51561aa SHA-1: 3e99848c9b93562bfe79458d59e9cf79d19c3d03 SHA-256: 75342e6fc49d7c239b03efa031e9300e62e850e06da6a3efee1c257a04d4741b

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate anomalies within the Equation Editor's native stream, strongly suggesting exploitation of CVE-2018-0798. This vulnerability allows for the delivery of a secondary payload, likely contained within the anomalous Ole10Native stream.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/9u.neeKzvV 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` `0513f2ecaab040481c9f3f1f11d215268c2744c9b3de63969b9d45978cb153a0`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/9u.neeKzvV	1425408 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.52, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `8873a79ddfce2049416a57309b5becf9e2324cca74fc9f4c8b6b961617335d55`	ole-package	OOXML xl/embeddings/9u.neeKzvV Ole10Native stream: OLE10NaTIVe	1412055 bytes

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