Office (OOXML) / .XLSX malware analysis — malicious · 383beb4614bb8470

MALICIOUS

Office (OOXML) / .XLSX

1.68 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-08-16

MD5: 8a28bea048673092f6f291059e164d95 SHA-1: 40c4291a8ce20cbab21b412c7116085cf11af4a1 SHA-256: 383beb4614bb8470073819d9eb649011048900ea1101c7a8b00f03ef0f9046c5

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1559.001 Component Object Model

The sample is an XLSX file containing an embedded OLE object, specifically a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and carries a payload-like Ole10Native stream, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/58Hwn8Apf.79R 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` `7bee05a44421810647aaf2d242b1228eca659d3eb6f9d2afe0a2ca589849231b`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/58Hwn8Apf.79R	2018816 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` `3da90239d753d16821997e579cbda4a3c3cf37b86c99bdd19cfc491d8839833c`	ole-package	OOXML xl/embeddings/58Hwn8Apf.79R Ole10Native stream: oLe10NaTIvE	2000807 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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