Office (OOXML) / .XLSX malware analysis — malicious · 4cd5fc82f7d1094e

MALICIOUS

Office (OOXML) / .XLSX

386.7 KB Created: 2021-01-18 22:58:55 UTC Authoring application: Microsoft Excel 15.0300

MD5: 6101d457ad1e2db80e960961e706f288 SHA-1: 075c6c06080a5662eb649c407d53bbf9b696a03f SHA-256: 4cd5fc82f7d1094ebe188a372dd682d24083ea423f0b49a057cfacc0af849ac4

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1559.001 Component Object Model and Distributed Component Object Model

The sample is an Excel file containing an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and likely carries a payload, exploiting CVE-2018-0798. The embedded OLE object and its native stream are suspicious due to high entropy and anomalous sizing, suggesting it's designed to execute arbitrary code.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject1.bin 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` `39630d675a860e770623fedde2df5df4be54e9f492264a2989d542d8ca9bd3f2`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	392704 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `678b3b7517825841d69fa7843681582f59f021b3cad0efa29c0d667ac916bc1c`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10nAtIVe	387156 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.

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