Office (OOXML) / .XLSX malware analysis — malicious · 41a9b8563d3ff22e

MALICIOUS

Office (OOXML) / .XLSX

1.43 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-01-20

MD5: d5819c62de7eed2ed35854d3cfd68fda SHA-1: 9c914459864373e5da85ce3ed8894963c465696d SHA-256: 41a9b8563d3ff22ea2a6f6664c17ca2493346117058678a15c16f679ed5f936d

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 OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. The embedded artifacts, ooxml_oleobject_00.bin and ooxml_oleobject_00_ole10native_00.bin, are likely components of the exploit chain.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/kDs.NkH 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` `6ada2936c06ef98e0e7837a547066d87e8338c4e2513f27c7ac9e5503494c526`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/kDs.NkH	1793536 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` `fb9c3a623f7b4bcfcaf409b1badb6861ed79608c66a453986a22cad82c055fcc`	ole-package	OOXML xl/embeddings/kDs.NkH Ole10Native stream: oLe10naTive	1776819 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

Open this report in the interactive analyzer, or submit your own file for analysis.