Office (OOXML) / .XLSX malware analysis — malicious · f431929ac6133e2a

MALICIOUS

Office (OOXML) / .XLSX

2.16 MB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-07-25

MD5: 32dd5c62c9ba03f651b221ed56d9e59e SHA-1: c8fa642909222d5e8814cce1c1510d1adc2f4b8f SHA-256: f431929ac6133e2a375488531a9e3f7452c657587ea5ccbd25a5980ac098eaac

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious File T1204.002 Malicious File: User Execution: Malicious Attachment T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an Office Open XML (OOXML) file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and carries a payload-like stream, strongly suggesting exploitation of CVE-2018-0798. This vulnerability allows for the execution of arbitrary code when the Equation Editor is loaded, leading to the delivery of a malicious payload.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/HHK2XXjVK.ghtxUcE 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` `0ce49396cbe14cd66dd5e892d42d590b3c03f115c99d2169163d5428524fd1bb`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/HHK2XXjVK.ghtxUcE	2552832 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` `4df5a14ccc179d9ee7a67af99d00672db6627affba14bff8ea79ea26a9c80358`	ole-package	OOXML xl/embeddings/HHK2XXjVK.ghtxUcE Ole10Native stream: OlE10NATIVe	2530723 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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