Office (OOXML) / .XLSX malware analysis — malicious · d42c4dc550b419c1

MALICIOUS

Office (OOXML) / .XLSX

1.64 MB Created: 2022-03-31 04:25:31 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-04-04

MD5: e8512e3bf62b0f28e06fd6be068d34e0 SHA-1: 365c15c5305ca27ad2243692760e05e9295e3fcc SHA-256: d42c4dc550b419c19c6aab434686157ee60ac9a056816ac0c32a574e76213b50

142 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an Excel file containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object exploits CVE-2018-0798, a vulnerability related to the Equation Editor's native stream. This suggests the file is designed to deliver a second-stage payload via this exploit. No document body or scripts were extracted, but the presence of the Equation Editor exploit is a strong indicator of malicious intent.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/QdCoF.8lS2y2 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` `57cad66a7a2ce8617ac5345c88dd659525ad4620ad1183b9242f4915575ea8da`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/QdCoF.8lS2y2	1971200 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` `b84a3e7489e56e9eccfa2d9a34d9d2bdbb13e312a378580031e25521c4c6fce9`	ole-package	OOXML xl/embeddings/QdCoF.8lS2y2 Ole10Native stream: Ole10Native	1953146 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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