Office (OOXML) / .XLSX malware analysis — malicious · 8f61dce0f0bc33e2

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 9d192a4361c7306893b334fadb9471d2 SHA-1: 4ba2040bc38aa9c14d0a9c25ba50104279de2e1d SHA-256: 8f61dce0f0bc33e2ccefc5ef5fd22ced3466ae4c5d2832bfa5d05d97b7e6a51f

142 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1559.001 Component Object Model

The sample is an Excel file containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. Heuristics indicate the presence of a payload within the Equation Editor's native stream, exploiting CVE-2018-0798. This suggests the file is designed to execute arbitrary code upon opening, likely leading to the download and execution of a secondary malicious payload.

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` `30e4407e9377a4204bf4f24294b0ed46a46625e8f457aa95fed29c33030f3fe2`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	214528 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`ooxml_oleobject_00_ole10native_00.bin` `829c4be8aacd00d8586ec17150c28e28ba540556525b4092fbd14ad9b4accd09`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10naTivE	210308 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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